[MCHECKSTYLE-427] Upgrade maven-invoker-plugin to 3.5.0

Adds support to run integration tests with Java 19+

pom.xml

@@ -380,6 +380,7 @@ under the License.
           <plugin>
             <groupId>org.apache.maven.plugins</groupId>
             <artifactId>maven-invoker-plugin</artifactId>
+            <version>3.5.0</version>
             <configuration>
               <goals>
                 <goal>clean</goal>

src/it/MCHECKSTYLE-214-basedir-resource/verify.groovy

@@ -17,6 +17,8 @@
  * specific language governing permissions and limitations
  * under the License.
  */
+import groovy.xml.XmlSlurper
+
 def buildLog = new File( basedir, 'build.log' )
 
 // LICENSE.txt has 2 errors, src/main/resources/README.txt has 1 error

src/it/checkstyle-goal/verify.groovy

@@ -17,6 +17,7 @@
  * specific language governing permissions and limitations
  * under the License.
  */
+import groovy.xml.XmlParser
 
 assert new File( basedir, 'target/checkstyle-cachefile' ).exists();
 assert new File( basedir, 'target/checkstyle-checker.xml' ).exists();

src/it/checkstyle-report/verify.groovy

@@ -17,6 +17,8 @@
  * specific language governing permissions and limitations
  * under the License.
  */
+import groovy.xml.XmlParser
+
 assert new File(basedir, 'target/site/checkstyle.html').exists();
 
 assert new File(basedir, 'target/checkstyle-cachefile').exists();