Attempt to fix auth error

.forgejo/workflows/build.yaml

@@ -16,10 +16,11 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@v2
 
-      - name: Set up JDK 21
-        uses: actions/setup-java@v2
-        with:
-          java-version: '21'
+      - name: Install JDK 21
+        run: |
+          sudo apt update
+          sudo apt install -y openjdk-21-jdk
+          java -version
 
       - name: Cache Maven dependencies
         uses: actions/cache@v2