remove gradle again

frontend/.github/workflows/build_app_android.yaml

@@ -1,7 +1,7 @@
 on:
   push:
-    branches:
-      - main
+    tags:
+      - 'v*'
 
 jobs:
   build:
@@ -24,13 +24,20 @@ jobs:
       - name: Setup android SDK
         uses: android-actions/setup-android@v3
       
+      - name: Install Flutter
+        uses: subosito/flutter-action@v2
+        with:
+          channel: stable
+          flutter-version: 3.22.0
+          cache: true
+
       - name: Infer version number from git tag
         id: version
         env: 
           REF_NAME: ${{ github.ref_name }}
         run:
           # remove the 'v' prefix from the tag name
-          echo "VERSION=${REF_NAME//v}" >> $GITHUB_OUTPUT
+          echo "VERSION_NAME=${REF_NAME//v}" >> $GITHUB_ENV
 
       - name: Load secrets from github
         run: |
@@ -46,5 +53,4 @@ jobs:
       - name: Run fastlane lane
         run: bundle exec fastlane deploy_testing
         working-directory: android
-        env:
-          VERSION_NAME: ${{ steps.version.VERSION }}
+        # the environment variable VERSION_NAME is implicitly available

frontend/android/.gitignore

@@ -1,3 +1,6 @@
+gradlew
+gradlew.bat
+gradle/
 /.gradle
 /captures/
 /local.properties

frontend/android/fastlane/Fastfile

@@ -7,10 +7,14 @@ platform :android do
 
   desc "Deploy a new version as a preview version"
   lane :deploy_testing do
+    version_name = ENV["VERSION_NAME"]
+
     sh(
-      "flutter build appbundle --release",
-      "--build-name=",
-      ENV["VERSION_NAME"],
+      "flutter",
+      "build",
+      "appbundle",
+      "--release",
+      "--build-name=#{version_name}",
       )
     
     upload_to_play_store(