Chore: Tidy up and Extend Learn Flutter Docs 📝

[nelsonic]

The contents of this repo is "OK" as a starting point but it feels like it could use some "polish" / updating.

Todo

• [x] Read through the repo and update to make it more beginner-friendly
• [x] Update any instructions & code samples as required
• [x] Finish any in-progress examples

Tidy Up

• [x] Review the open PRs: https://github.com/dwyl/learn-flutter/pulls

• [x] Random GIF: https://github.com/dwyl/learn-flutter/pull/39
• [x] How to use Environment Variables in a Flutter App: https://github.com/dwyl/learn-flutter/pull/41

• [x] Review what is useable on the branches: https://github.com/dwyl/learn-flutter/branches
  • [x] DELETE if no longer relevant

[nelsonic]

@LuchoTurtle if you can review this doc and update it, it would be a huge help! 🙏 I've already deleted my old ("stale") branch. ✂️ Please liberally update the grammar/style of writing to match our other projects. 📝 Anything else you think of along the way, comment! 💬

[nelsonic]

@LuchoTurtle's PR: https://github.com/dwyl/learn-flutter/pull/69 🎉

[nelsonic]

@LuchoTurtle to create a micro-PR to add GitHub Actions to this repo so that we can check everything is working. 🙏 As per: https://github.com/dwyl/flutter-counter-example/pull/7#issuecomment-1316625719

[LuchoTurtle]

@nelsonic you should find it here -> https://github.com/dwyl/learn-flutter/pull/71

[nelsonic]

Thanks. Merged. Please confirm Working. 🤞

[LuchoTurtle]

Similarly to what happened in https://github.com/dwyl/flutter-counter-example/issues/6#issuecomment-1316782820, the CI should work when working with the latest Flutter version, as it's the case with #69 . After this PR is merged, it should work 😄

[nelsonic]

Gotcha. Thanks. 👌