Add maven caching to GitHub build action

Author: fabapp2

.github/workflows/mvn-build.yml

@@ -16,5 +16,6 @@ jobs:
         with:
           java-version: '11'
           distribution: 'adopt'
+          cache: 'maven'
       - name: Build with Maven
         run: mvn --update-snapshots -DtrimStackTrace=false  -Dsurefire.useFile=false -DskipITs verify