Configure signing for release builds

.gitea/workflows/android.yml

@@ -15,12 +15,21 @@ jobs:
       - name: Setup JDK
         uses: actions/setup-java@v4
         with:
-          java-version: '17'
+          java-version: '21'
           distribution: 'temurin'
 
       - name: Setup Android SDK
         uses: android-actions/setup-android@v2
 
+      - name: Setup Keystore
+        run: |
+          echo "${{ secrets.ANDROIDKEYSTOREBASE64 }}" | base64 -d > helldivers.keystore
+        env:
+          ANDROIDKEYSTOREPATH: helldivers.keystore
+          ANDROIDKEYSTOREPASS: ${{ secrets.ANDROIDKEYSTOREPASS }}
+          ANDROIDKEYALIAS: ${{ secrets.ANDROIDKEYALIAS }}
+          ANDROIDKEYPASS: ${{ secrets.ANDROIDKEYPASS }}
+
       - name: Build with Gradle
         run: |
           chmod +x ./gradlew