Added jacoco plugin for showing code coverage info in a badge at the …

…README.md

.github/workflows/maven.yml

@@ -42,7 +42,7 @@ jobs:
         if [[ `git status --porcelain` ]]; then
           git config --global user.name 'Roland Speckmeier'
           git config --global user.email '[email protected]'
-          git add '*.svg'
+          git add .github/badges/jacoco.svg
           git commit -m "Autogenerated JaCoCo coverage badge"
           git push
         fi