Only create signed APK if secrets are available (#234)

Author: chvp

.github/workflows/ci.yml

@@ -64,12 +64,20 @@ jobs:
     - name: Build
       run: |
         ./gradlew assemble
+    - name: Sign APK
+      if: env.KEYSTORE_FILE
+      env:
+        KEYSTORE_FILE: ${{ secrets.KEYSTORE_FILE }}
+      run: |
         $ANDROID_SDK_ROOT/build-tools/34.0.0/zipalign -v -p 4 app/build/outputs/apk/release/app-release-unsigned.apk app/build/outputs/apk/release/app-release-unsigned-aligned.apk
         echo "${{ secrets.KEYSTORE_FILE }}" | base64 -d > keystore.jks
         echo "${{ secrets.KEYSTORE_PASSWORD }}" | $ANDROID_SDK_ROOT/build-tools/34.0.0/apksigner sign --ks keystore.jks --out app-release.apk app/build/outputs/apk/release/app-release-unsigned-aligned.apk
         $ANDROID_SDK_ROOT/build-tools/34.0.0/apksigner verify app-release.apk
     - name: Archive production APK
       uses: actions/upload-artifact@v4
+      if: env.KEYSTORE_FILE
+      env:
+        KEYSTORE_FILE: ${{ secrets.KEYSTORE_FILE }}
       with:
         name: apk
         path: app-release.apk