Composer Unused

[MGatner]

Composer Unused 0.8.1 has a couple new features desirable for this kit:

• Formatters: Besides the default formatter results can be output as GitHub annotations
• File configuration: Now reads in supplemental information from a config file

This PR implements the new GitHub formatter (though in most cases it should be detected automatically) and adds an example config file to the Template.

[kenjis]

@MGatner These lines are not necessary:

devkit/src/Template/.github/workflows/unused.yml

Lines 50 to 58 in e124bff

	- name: Create PHPStan cache directory
	run: mkdir -p build/phpstan
	- name: Cache PHPStan results
	uses: actions/cache@v2
	with:
	path: build/phpstan
	key: ${{ runner.os }}-phpstan-${{ github.sha }}
	restore-keys: ${{ runner.os }}-phpstan-

[MGatner]

You are very right! Those must have crept in a while ago on a copy-paste boat.