Build release with 'external' release.keystore

Author: CAMOBAP

.github/workflows/android.yml

@@ -31,7 +31,14 @@ jobs:
         with:
           java-version: 1.8
 
-      - run: ./gradlew assembleRelease --stacktrace
+      - run: echo ${{ secrets.SIGNING_STORE_FILE }} | base64 -d > app/release.keystore
+
+      - run: |
+          ./gradlew assembleRelease --stacktrace \
+            -Pandroid.injected.signing.store.file=$PWD/app/release.keystore \
+            -Pandroid.injected.signing.store.password=${{ secrets.SIGNING_STORE_PASSWORD }}
+            -Pandroid.injected.signing.key.alias=${{ secrets.SIGNING_KEY_ALIAS }}
+            -Pandroid.injected.signing.key.password=${{ secrets.SIGNING_KEY_PASSWORD }}
 
       - uses: actions/upload-artifact@v1
         with: