Github Action for Flutter Build, Test, Release and Upload app

main.yml

# This is a basic workflow to help you get started with Actions

name: Test, Build, Release Demo app to Azure Storgae
# name: Test, Build and Release apk
# Controls when the action will run. Triggers the workflow on push or pull request
# events but only for the master branch
on:
  push:
    branches: [ master ]

# A workflow run is made up of one or more jobs that can run sequentially or in parallel
jobs:
  # This workflow contains a single job called "build"
  build:
    runs-on: ubuntu-latest
    steps:
    - uses: actions/checkout@v1
    - uses: actions/setup-java@v1
      with:
        java-version: '12.x'
    - uses: subosito/flutter-action@v1
      with:
        channel: 'dev'
    - run: flutter pub get
    - name: 'Run Test(s)'
      run: flutter test
    - name: 'Build Demo Apk'
      run: flutter clean && flutter build apk --target lib/main_demo.dart --target-platform android-arm --flavor demo
    - name: 'Upload Apk'
      uses: wei/curl@v1
      with:
        args: -X POST 'https://--your-url---.com/api/UploadApk?filename=release.apk' -F file=@build/app/outputs/apk/demo/release/app-demo-release.apk
        

You can use

flutter clean && flutter build apk only but then you will need to change file location in last line