Update main.yml

Create Android secrets file.

.github/workflows/main.yml

@@ -11,7 +11,13 @@ jobs:
     steps:
     - name: Checkout code
       uses: actions/checkout@v2
-
+
+    - name: Setup android secret
+      uses: finnp/[email protected]
+      env:
+        FILE_NAME: "android/secrets.properties"
+        FILE_DATA: "MAPS_API_KEY=${{ secrets.SERVICE_ACCOUNT_JSON }}"
+
     - name: Set up Flutter
       uses: subosito/flutter-action@v2