How I build and release Flutter side projects on iOS https://twitter.com/luke_pighetti/status/1530156415611969537

Fastfile

default_platform(:ios)

APPLE_ISSUER_ID = ENV["APPLE_ISSUER_ID"]
APPLE_KEY_CONTENT = ENV["APPLE_KEY_CONTENT"]
APPLE_KEY_ID = ENV["APPLE_KEY_ID"]
DEVELOPER_APP_ID = ENV["DEVELOPER_APP_ID"]
DEVELOPER_APP_IDENTIFIER = ENV["DEVELOPER_APP_IDENTIFIER"]
GIT_AUTHORIZATION = ENV["GIT_AUTHORIZATION"]
GITHUB_RUN_NUMBER = ENV["GITHUB_RUN_NUMBER"]
PROVISIONING_PROFILE_SPECIFIER = ENV["PROVISIONING_PROFILE_SPECIFIER"]
VERSION_NUMBER = ENV["VERSION_NUMBER"]

platform :ios do
  lane :beta do
    setup_ci()

    api_key = app_store_connect_api_key(
      issuer_id: APPLE_ISSUER_ID,
      key_content: APPLE_KEY_CONTENT,            
      key_id: APPLE_KEY_ID,
    )
    
    cocoapods(
      clean_install: true
    )

    match(
      type: 'appstore',
      app_identifier: DEVELOPER_APP_IDENTIFIER,
      git_basic_authorization: Base64.strict_encode64(GIT_AUTHORIZATION),
      readonly: true,
      api_key: api_key,
    )

    increment_version_number(
      version_number: VERSION_NUMBER
    )

    increment_build_number(
      build_number: GITHUB_RUN_NUMBER.to_i
    )

    gym(
      configuration: "Release",
      workspace: "Runner.xcworkspace",
      scheme: "your_schema",
      export_method: "app-store",
      export_options: {
        provisioningProfiles: { 
            DEVELOPER_APP_ID => PROVISIONING_PROFILE_SPECIFIER
        }
      }
    )

    pilot(
      apple_id: DEVELOPER_APP_ID,
      app_identifier: DEVELOPER_APP_IDENTIFIER,
      ipa: "./Runner.ipa",
      skip_waiting_for_build_processing: true,
    )
  end
end

testflight.yml

name: CD
on:
  workflow_dispatch:

jobs:
  deploy:
    name: Deploy to TestFlight
    runs-on: macos-latest
    timeout-minutes: 60

    steps:
      - uses: actions/checkout@v2
      - uses: subosito/flutter-action@v2
        with:
          channel: stable
      - run: flutter pub get
      - uses: ruby/setup-ruby@v1
        with:
          ruby-version: "2.7.2"
      - uses: maierj/fastlane-action@v2.2.0
        with:
          lane: beta
          subdirectory: "ios"
        env:
          APP_STORE_CONNECT_TEAM_ID: "${{ secrets.APP_STORE_CONNECT_TEAM_ID }}"
          APPLE_ISSUER_ID: "${{ secrets.APPLE_ISSUER_ID }}"
          APPLE_KEY_CONTENT: "${{ secrets.APPLE_KEY_CONTENT }}"
          APPLE_KEY_ID: "${{ secrets.APPLE_KEY_ID }}"
          DEVELOPER_APP_ID: "${{ secrets.DEVELOPER_APP_ID }}"
          DEVELOPER_APP_IDENTIFIER: "${{ secrets.DEVELOPER_APP_IDENTIFIER }}"
          DEVELOPER_PORTAL_TEAM_ID: "${{ secrets.DEVELOPER_PORTAL_TEAM_ID }}"
          FASTLANE_APPLE_APPLICATION_SPECIFIC_PASSWORD: "${{ secrets.FASTLANE_APPLE_APPLICATION_SPECIFIC_PASSWORD }}"
          FASTLANE_APPLE_ID: "${{ secrets.FASTLANE_APPLE_ID }}"
          GIT_AUTHORIZATION: "${{ secrets.GIT_AUTHORIZATION }}"
          GITHUB_RUN_NUMBER: "${{ github.run_number }}"
          MATCH_PASSWORD: "${{ secrets.MATCH_PASSWORD }}"
          PROVISIONING_PROFILE_SPECIFIER: "${{ secrets.PROVISIONING_PROFILE_SPECIFIER }}"
          VERSION_NUMBER: "1.0.0"

Secrets

Triggering method