chore: update GitHub action workflow (#126)

* Create flutter-ci.yml

This ci does whatever the previous ci (cleaner code tho) did but it additionally uploads the apk for each PR to github artifacts which can be donwloaded by the qa team to make their testing easier. So basically the tester from qa team will not have to use an android emulator or install flutter to test PRs on this repo anymore. Just download the artifact from below each PR :)

* Delete main.yml

* Update flutter-ci.yml

Won't skip warnings hence removed for now

.github/workflows/flutter-ci.yml

@@ -0,0 +1,48 @@
+name: Flutter CI
+
+on:
+  push:
+    branches:
+      - develop
+  pull_request:
+    branches:
+      - develop
+
+jobs:
+  build:
+    strategy:
+      matrix:
+        platform: [ubuntu-latest, macos-latest]
+    runs-on: ${{ matrix.platform }}
+    steps:
+
+    # Setup Java environment in order to build the Android app.
+    - uses: actions/checkout@v2.3.1
+    - uses: actions/setup-java@v1.4.0
+      with:
+        java-version: '12.x'
+
+    # Setup the flutter environment.
+    - uses: subosito/flutter-action@v1.3.2
+      with:
+        channel: 'beta'
+
+    # Get flutter dependencies.
+    - run: flutter pub get
+
+    # Run tests for our flutter project once we add unit tests.
+    # - run: flutter test
+
+    # Build apk.
+    - run: flutter build apk
+
+    # Build ios
+    - name: Run ios build
+      if: ${{ matrix.platform == 'macos-latest'}}
+      run: flutter build ios --release --no-codesign 
+
+    # Upload generated apk to the artifacts.
+    - uses: actions/upload-artifact@v2
+      with:
+        name: release-apk
+        path: build/app/outputs/apk/release/app-release.apk