Downgrade Upload Google Play Action to 1.0.15

To fix this: r0adkll/upload-google-play#80

Author: koenidv

.github/workflows/deploy.yaml

@@ -37,7 +37,7 @@ jobs:
         run: echo '${{ secrets.SERVICE_ACCOUNT_JSON }}' > service_account.json
 
       - name: Deploy to Production
-        uses: r0adkll/upload-google-play@v1
+        uses: r0adkll/upload-google-play@v1.0.15
         with:
           serviceAccountJson: service_account.json
           packageName: de.koenidv.sph