Use github action setup-java@v4 instead of v2

* The CI Pipeline was not working anymore. Github seems to require this change to allow the CI to be working again

Author: Stefan Hahmann

.github/workflows/build-main.yml

@@ -15,7 +15,7 @@ jobs:
     steps:
       - uses: actions/checkout@v2
       - name: Set up Java
-        uses: actions/setup-java@v2
+        uses: actions/setup-java@v4
         with:
           java-version: '8'
           distribution: 'zulu'

.github/workflows/build-pr.yml

@@ -13,7 +13,7 @@ jobs:
     steps:
       - uses: actions/checkout@v2
       - name: Set up Java
-        uses: actions/setup-java@v2
+        uses: actions/setup-java@v4
         with:
           java-version: '8'
           distribution: 'zulu'