JCRVLT-393 compile ITs for Java8 to support building on Java13

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/commons/filevault-package-maven-plugin/trunk@1871759 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/.travis.yml b/.travis.yml
index 1dee885..2b06eaf 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -42,8 +42,7 @@
     # available build differs among platforms.
     - JDK="adopt@1.8"
     - JDK="adopt@1.11"
-    # cannot build with latest JDK yet, because source=6 is no longer supported in the ITs
-    # - JDK="adopt@1.13"
+    - JDK="adopt@1.13"
 before_install:
   # Download the script
   - curl "${GRAVIS}.install-jdk-travis.sh" --output ~/.install-jdk-travis.sh
diff --git a/src/test/java/org/apache/jackrabbit/filevault/maven/packaging/it/ProjectBuilder.java b/src/test/java/org/apache/jackrabbit/filevault/maven/packaging/it/ProjectBuilder.java
index d2f8de7..10b2081 100644
--- a/src/test/java/org/apache/jackrabbit/filevault/maven/packaging/it/ProjectBuilder.java
+++ b/src/test/java/org/apache/jackrabbit/filevault/maven/packaging/it/ProjectBuilder.java
@@ -122,6 +122,8 @@
 
         testProperties.put("plugin.version", getPluginVersion());
         testProperties.put("testcontent.directory", new File("target/test-classes/test-content").getAbsolutePath());
+        testProperties.put("maven.compiler.source", "1.8");
+        testProperties.put("maven.compiler.target", "1.8");
     }
 
     /**