Set src/target to Java 8 in integration tests
diff --git a/source-release/src/test/resources/basics/pom.xml b/source-release/src/test/resources/basics/pom.xml
index 33b30cd..2edaf8b 100644
--- a/source-release/src/test/resources/basics/pom.xml
+++ b/source-release/src/test/resources/basics/pom.xml
@@ -67,6 +67,14 @@
           </execution>
         </executions>
       </plugin>
+      <plugin>
+        <artifactId>maven-compiler-plugin</artifactId>
+        <version>3.11.0</version>
+        <configuration>
+          <source>1.8</source>
+          <target>1.8</target>
+        </configuration>
+      </plugin>
     </plugins>
   </build>
 </project>
diff --git a/source-release/src/test/resources/build-output-dir/pom.xml b/source-release/src/test/resources/build-output-dir/pom.xml
index db2257a..4fb644b 100644
--- a/source-release/src/test/resources/build-output-dir/pom.xml
+++ b/source-release/src/test/resources/build-output-dir/pom.xml
@@ -67,6 +67,14 @@
           </execution>
         </executions>
       </plugin>
+      <plugin>
+        <artifactId>maven-compiler-plugin</artifactId>
+        <version>3.11.0</version>
+        <configuration>
+          <source>1.8</source>
+          <target>1.8</target>
+        </configuration>
+      </plugin>
     </plugins>
   </build>
 </project>
diff --git a/source-release/src/test/resources/ci-excludes/pom.xml b/source-release/src/test/resources/ci-excludes/pom.xml
index d47d1ad..a60970e 100644
--- a/source-release/src/test/resources/ci-excludes/pom.xml
+++ b/source-release/src/test/resources/ci-excludes/pom.xml
@@ -62,6 +62,14 @@
           </execution>
         </executions>
       </plugin>
+      <plugin>
+        <artifactId>maven-compiler-plugin</artifactId>
+        <version>3.11.0</version>
+        <configuration>
+          <source>1.8</source>
+          <target>1.8</target>
+        </configuration>
+      </plugin>
     </plugins>
   </build>
 </project>
diff --git a/source-release/src/test/resources/ide-excludes/pom.xml b/source-release/src/test/resources/ide-excludes/pom.xml
index 7208c24..210236f 100644
--- a/source-release/src/test/resources/ide-excludes/pom.xml
+++ b/source-release/src/test/resources/ide-excludes/pom.xml
@@ -67,6 +67,14 @@
           </execution>
         </executions>
       </plugin>
+      <plugin>
+        <artifactId>maven-compiler-plugin</artifactId>
+        <version>3.11.0</version>
+        <configuration>
+          <source>1.8</source>
+          <target>1.8</target>
+        </configuration>
+      </plugin>
     </plugins>
   </build>
 </project>
diff --git a/source-release/src/test/resources/misc-excludes/pom.xml b/source-release/src/test/resources/misc-excludes/pom.xml
index d8444c0..1f32650 100644
--- a/source-release/src/test/resources/misc-excludes/pom.xml
+++ b/source-release/src/test/resources/misc-excludes/pom.xml
@@ -67,6 +67,14 @@
           </execution>
         </executions>
       </plugin>
+      <plugin>
+        <artifactId>maven-compiler-plugin</artifactId>
+        <version>3.11.0</version>
+        <configuration>
+          <source>1.8</source>
+          <target>1.8</target>
+        </configuration>
+      </plugin>
     </plugins>
   </build>
 </project>
diff --git a/source-release/src/test/resources/output-dir-contains-src-name/pom.xml b/source-release/src/test/resources/output-dir-contains-src-name/pom.xml
index 392d0ef..abe0f6b 100644
--- a/source-release/src/test/resources/output-dir-contains-src-name/pom.xml
+++ b/source-release/src/test/resources/output-dir-contains-src-name/pom.xml
@@ -80,6 +80,14 @@
           </execution>
         </executions>
       </plugin>
+      <plugin>
+        <artifactId>maven-compiler-plugin</artifactId>
+        <version>3.11.0</version>
+        <configuration>
+          <source>1.8</source>
+          <target>1.8</target>
+        </configuration>
+      </plugin>
     </plugins>
   </build>
 </project>
diff --git a/source-release/src/test/resources/shared-resources/pom.xml b/source-release/src/test/resources/shared-resources/pom.xml
index d2c594a..94daa04 100644
--- a/source-release/src/test/resources/shared-resources/pom.xml
+++ b/source-release/src/test/resources/shared-resources/pom.xml
@@ -84,6 +84,14 @@
           </execution>
         </executions>
       </plugin>
+      <plugin>
+        <artifactId>maven-compiler-plugin</artifactId>
+        <version>3.11.0</version>
+        <configuration>
+          <source>1.8</source>
+          <target>1.8</target>
+        </configuration>
+      </plugin>
     </plugins>
   </build>
 </project>
diff --git a/source-release/src/test/resources/src-contains-ide-files/pom.xml b/source-release/src/test/resources/src-contains-ide-files/pom.xml
index bc70acf..bae074f 100644
--- a/source-release/src/test/resources/src-contains-ide-files/pom.xml
+++ b/source-release/src/test/resources/src-contains-ide-files/pom.xml
@@ -66,6 +66,14 @@
           </execution>
         </executions>
       </plugin>
+      <plugin>
+        <artifactId>maven-compiler-plugin</artifactId>
+        <version>3.11.0</version>
+        <configuration>
+          <source>1.8</source>
+          <target>1.8</target>
+        </configuration>
+      </plugin>
     </plugins>
   </build>
 </project>
diff --git a/source-release/src/test/resources/src-contains-output-dir-name/pom.xml b/source-release/src/test/resources/src-contains-output-dir-name/pom.xml
index b567db2..b04855d 100644
--- a/source-release/src/test/resources/src-contains-output-dir-name/pom.xml
+++ b/source-release/src/test/resources/src-contains-output-dir-name/pom.xml
@@ -67,6 +67,14 @@
           </execution>
         </executions>
       </plugin>
+      <plugin>
+        <artifactId>maven-compiler-plugin</artifactId>
+        <version>3.11.0</version>
+        <configuration>
+          <source>1.8</source>
+          <target>1.8</target>
+        </configuration>
+      </plugin>
     </plugins>
   </build>
 </project>
diff --git a/source-release/src/test/resources/zip-and-tar/pom.xml b/source-release/src/test/resources/zip-and-tar/pom.xml
index e349491..dc5c132 100644
--- a/source-release/src/test/resources/zip-and-tar/pom.xml
+++ b/source-release/src/test/resources/zip-and-tar/pom.xml
@@ -68,6 +68,14 @@
           </execution>
         </executions>
       </plugin>
+      <plugin>
+        <artifactId>maven-compiler-plugin</artifactId>
+        <version>3.11.0</version>
+        <configuration>
+          <source>1.8</source>
+          <target>1.8</target>
+        </configuration>
+      </plugin>
     </plugins>
   </build>
 </project>