feat(mime): add `gsheet` default extension to map #43

	name: Dart CI

	on:
	schedule:
	# “At 00:00 (UTC) on Sunday.”
	- cron: '0 0 * * 0'
	push:
	branches: [ main ]
	paths:
	- '.github/workflows/mime.yml'
	- 'pkgs/mime/**'
	pull_request:
	branches: [ main ]
	paths:
	- '.github/workflows/mime.yml'
	- 'pkgs/mime/**'

	jobs:
	build:
	runs-on: ubuntu-latest
	defaults:
	run:
	working-directory: pkgs/mime/

	strategy:
	matrix:
	os: [ubuntu-latest]
	sdk: [3.2, dev]
	steps:
	# These are the latest versions of the github actions; dependabot will
	# send PRs to keep these up-to-date.
	- uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
	- uses: dart-lang/setup-dart@0a8a0fc875eb934c15d08629302413c671d3f672

	- name: Install dependencies
	run: dart pub get

	- name: Verify formatting
	run: dart format --output=none --set-exit-if-changed .

	- name: Analyze project source
	run: dart analyze --fatal-infos

	- name: Run tests
	run: dart test

Provide feedback