Update mikepenz/action-junit-report action to v4 (#26)

Author: nedtwigg

.github/workflows/ci.yml

@@ -33,7 +33,7 @@ jobs:
       - name: gradlew build
         run: ./gradlew build
       - name: junit result
-        uses: mikepenz/action-junit-report@v3
+        uses: mikepenz/action-junit-report@v4
         if: always() # always run even if the previous step fails
         with:
           check_name: JUnit ${{ matrix.jre }} ${{ matrix.os }}