Require JDK 11 and support JDK 21 at build time (#310)

* Support JDK 21

* Update groovy to latest

* Drop jdk 8, add jdk 11 and 21
diff --git a/.github/workflows/maven-verify.yml b/.github/workflows/maven-verify.yml
index d59fd67..7b15dd4 100644
--- a/.github/workflows/maven-verify.yml
+++ b/.github/workflows/maven-verify.yml
@@ -31,7 +31,7 @@
     strategy:
       matrix:
         os: [ubuntu-latest]
-        java: [8, 17]
+        java: [11, 17, 21]
       fail-fast: false
 
     runs-on: ${{ matrix.os }}
diff --git a/core-it-suite/src/test/resources-filtered/bootstrap.txt b/core-it-suite/src/test/resources-filtered/bootstrap.txt
index 439d9fe..0422df0 100644
--- a/core-it-suite/src/test/resources-filtered/bootstrap.txt
+++ b/core-it-suite/src/test/resources-filtered/bootstrap.txt
@@ -16,8 +16,8 @@
 org.apache.ant:ant:1.10.8
 org.apache.commons:commons-text:1.10.0
 org.apache.geronimo.specs:geronimo-jcdi_2.0_spec:1.3
-org.apache.groovy:groovy-ant:4.0.6
-org.apache.groovy:groovy:4.0.6
+org.apache.groovy:groovy-ant:4.0.15
+org.apache.groovy:groovy:4.0.15
 org.apache.maven.extensions:maven-extensions:40:pom
 org.apache.maven.its.plugins.class-loader:dep-c:${project.version}
 org.apache.maven.its.plugins:maven-it-plugin-active-collection:${project.version}
diff --git a/core-it-suite/src/test/resources/mng-7045/pom.xml b/core-it-suite/src/test/resources/mng-7045/pom.xml
index 48848f6..0ab9bb2 100644
--- a/core-it-suite/src/test/resources/mng-7045/pom.xml
+++ b/core-it-suite/src/test/resources/mng-7045/pom.xml
@@ -43,13 +43,13 @@
           <dependency>
             <groupId>org.apache.groovy</groupId>
             <artifactId>groovy-ant</artifactId>
-            <version>4.0.6</version>
+            <version>4.0.15</version>
             <scope>runtime</scope>
           </dependency>
           <dependency>
             <groupId>org.apache.groovy</groupId>
             <artifactId>groovy</artifactId>
-            <version>4.0.6</version>
+            <version>4.0.15</version>
             <scope>runtime</scope>
           </dependency>
         </dependencies>
diff --git a/pom.xml b/pom.xml
index 29dc342..43809b5 100644
--- a/pom.xml
+++ b/pom.xml
@@ -151,6 +151,32 @@
   <build>
     <pluginManagement>
       <plugins>
+        <!-- Remove when Parent 41 used -->
+        <plugin>
+          <groupId>com.diffplug.spotless</groupId>
+          <artifactId>spotless-maven-plugin</artifactId>
+          <version>2.40.0</version>
+          <configuration>
+            <java>
+              <!-- orders of used formatters are important MPOM-376 -->
+              <!-- eg. palantir override importOrder, so should be first -->
+              <palantirJavaFormat>
+                <version>2.38.0</version>
+              </palantirJavaFormat>
+              <removeUnusedImports />
+            </java>
+            <pom>
+              <sortPom>
+                <expandEmptyElements>false</expandEmptyElements>
+                <!-- https://issues.apache.org/jira/browse/MRELEASE-1111 -->
+                <spaceBeforeCloseEmptyElement>true</spaceBeforeCloseEmptyElement>
+              </sortPom>
+            </pom>
+            <upToDateChecking>
+              <enabled>true</enabled>
+            </upToDateChecking>
+          </configuration>
+        </plugin>
         <plugin>
           <groupId>org.apache.maven.plugins</groupId>
           <artifactId>maven-surefire-plugin</artifactId>