Adding setup java step to CI

Author: folkengine

.github/workflows/CI.yml

@@ -27,7 +27,12 @@ jobs:
       # Checks-out your repository under $GITHUB_WORKSPACE, so your job can access it
       - name: Checkout sources
         uses: actions/checkout@v4
+      - name: Setup Java
+        uses: actions/setup-java@v4
+        with:
+          distribution: 'temurin'
+          java-version: 18
       - name: Setup Gradle
-        uses: gradle/actions/setup-gradle@v3
+        uses: gradle/actions/setup-gradle@v4
       - name: Build with Gradle
         run: ./gradlew build