fix: add release/publish workflows

[falconandy]

Added 2 workflows:

1. release (manual) - bumps version, creates/pushes a commit/tag.
2. publish (auto-triggered on push) - publishes new version to pub.dev

release workflow:

A deploy key (public part) should be added to the repo with write access. Private part of the key should be added as a repo secret DEPLOY_KEY.

publish workflow:
https://dart.dev/tools/pub/automated-publishing#publishing-packages-using-github-actions

Need to setup Publishing from GitHub Actions in package settings:

I use latest Flutter/Dart versions: 3.13.3/3.1.1. example/pubspec.lock was updated by flutter pub get command (also cupertino_icons should be bumped to ^1.0.6 in example/pubspec.yaml)

I think the example should be updated to recent Flutter/Dart versions. It doesn't work for me (may depend on Android Studio version in addition to Flutter/Dart versions).

flutter analyze command outputs 12 info messages and 2 warnings. I fixed the 2 warnings. For now I use command flutter analyze --no-fatal-infos to ignore info messages. --no-fatal-infos flag can be removed after we update the example.

Info messages:

Analyzing example...                                                    

   info • The import of 'package:flutter/foundation.dart' is unnecessary because all of the used elements are also provided by the import of 'package:flutter/material.dart' • lib/app_state.dart:2:8 • unnecessary_import
   info • 'headline5' is deprecated and shouldn't be used. Use headlineSmall instead. This feature was deprecated after v3.1.0-0.0.pre • lib/deviceid_sessionid.dart:16:66 • deprecated_member_use
   info • 'headline5' is deprecated and shouldn't be used. Use headlineSmall instead. This feature was deprecated after v3.1.0-0.0.pre • lib/deviceid_sessionid.dart:31:67 • deprecated_member_use
   info • 'headline5' is deprecated and shouldn't be used. Use headlineSmall instead. This feature was deprecated after v3.1.0-0.0.pre • lib/event_form.dart:25:58 • deprecated_member_use
   info • 'headline5' is deprecated and shouldn't be used. Use headlineSmall instead. This feature was deprecated after v3.1.0-0.0.pre • lib/flush_thresholds_form.dart:42:68 • deprecated_member_use
   info • 'headline5' is deprecated and shouldn't be used. Use headlineSmall instead. This feature was deprecated after v3.1.0-0.0.pre • lib/group_form.dart:32:68 • deprecated_member_use
   info • 'headline5' is deprecated and shouldn't be used. Use headlineSmall instead. This feature was deprecated after v3.1.0-0.0.pre • lib/group_identify_form.dart:44:67 • deprecated_member_use
   info • 'headline5' is deprecated and shouldn't be used. Use headlineSmall instead. This feature was deprecated after v3.1.0-0.0.pre • lib/identify_form.dart:38:61 • deprecated_member_use
   info • 'bodyText1' is deprecated and shouldn't be used. Use bodyLarge instead. This feature was deprecated after v3.1.0-0.0.pre • lib/my_app.dart:115:67 • deprecated_member_use
   info • 'headline5' is deprecated and shouldn't be used. Use headlineSmall instead. This feature was deprecated after v3.1.0-0.0.pre • lib/revenue_form.dart:41:60 • deprecated_member_use
   info • 'headline5' is deprecated and shouldn't be used. Use headlineSmall instead. This feature was deprecated after v3.1.0-0.0.pre • lib/user_id_form.dart:22:68 • deprecated_member_use
   info • 'headline5' is deprecated and shouldn't be used. Use headlineSmall instead. This feature was deprecated after v3.1.0-0.0.pre • lib/user_id_form.dart:30:60 • deprecated_member_use

[justin-fiedler]

Thanks @falconandy. The example was working for me locally.

What platform did you try? iOS/Android/Web?

My flutter --version is

Flutter 3.3.8 • channel stable • https://github.com/flutter/flutter.git
Framework • revision 52b3dc25f6 (12 months ago) • 2022-11-09 12:09:26 +0800
Engine • revision 857bd6b74c
Tools • Dart 2.18.4 • DevTools 2.15.0

[github-actions]

🎉 This PR is included in version 3.16.1 🎉

The release is available on GitHub release

Your semantic-release bot 📦🚀

[falconandy]

@justin-fiedler

I tried on Ubuntu + Android Emulator.

Flutter 3.13.3 • channel stable • https://github.com/flutter/flutter.git
Framework • revision 2524052335 (9 weeks ago) • 2023-09-06 14:32:31 -0700
Engine • revision b8d35810e9
Tools • Dart 3.1.1 • DevTools 2.25.0