updated contributing.md file #129

	name: Main Branch Formatting CI

	on:
	pull_request:
	branches:
	- master

	jobs:
	format:
	runs-on: ubuntu-latest

	steps:
	- uses: actions/checkout@v3
	with:
	ref: ${{ github.event.pull_request.head.ref }}

	- uses: dart-lang/setup-dart@9a04e6d73cca37bd455e0608d7e5092f881fd603

	- name: Perform formatting
	run: find . -name ".dart" ! -path '/gen/*' ! -name 'injection.config.dart' \| tr '\n' ' ' \| xargs dart format

	# Perform the commit at the end to make sure tests above don't fail
	- name: Commit formatting changes
	run: \|
	git config --global user.name "github-actions"
	git config --global user.email "[email protected]"
	git add .
	git diff-index --quiet HEAD \|\| (git commit -m 'Automatic formatting' && git push)

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