Update Flutter SDK and dependencies. Fix analyzer issues. #158

	name: Build & Deploy to GitHub Pages

	on:
	push:
	branches:
	- main
	pull_request:
	branches:
	- main

	jobs:
	build:
	name: Build
	runs-on: ubuntu-latest

	steps:
	- name: Checkout code
	uses: actions/checkout@v2

	- name: Cache Flutter dependencies
	uses: actions/cache@v1
	with:
	path: /opt/hostedtoolcache/flutter
	key: ${{ runner.OS }}-flutter-install-cache-${{ env.flutter_version }}
	- name: Install Flutter
	uses: subosito/flutter-action@v2
	with:
	channel: 'stable'

	- name: Get dependencies
	run: flutter pub get

	- name: Analyze project
	run: flutter analyze

	- name: Test project
	run: flutter test

	- name: Build release project
	run: flutter build web

	- name: Upload production-ready build files
	uses: actions/upload-artifact@v2
	with:
	name: production-files
	path: ./build/web

	deploy:
	name: Deploy
	needs: build
	runs-on: ubuntu-latest
	if: github.ref == 'refs/heads/main'

	steps:
	- name: Download artifact
	uses: actions/download-artifact@v2
	with:
	name: production-files
	path: ./build

	- name: Deploy to gh-pages
	uses: peaceiris/actions-gh-pages@v3
	with:
	github_token: ${{ secrets.GH_TOKEN }}
	publish_dir: ./build

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