Make markdown-lint a required CI check

[hcgatewood]

Make markdown-lint a required CI check

The check has been active for 1+ months, and has support parity with the other required checks.

The win here is automatically enforcing a minimal set of Markdown standards -- only catches actual issues, is not meant to be intrusive 🙂

Job ref:

magma/.github/workflows/docs-workflow.yml

Lines 32 to 48 in 136ad85

	# Fail if Markdown doesn't pass linter
	markdown-lint:
	needs: path_filter
	if: ${{ needs.path_filter.outputs.should_not_skip == 'true' }}
	name: Markdown lint check
	runs-on: ubuntu-latest
	env:
	MAGMA_ROOT: "${{ github.workspace }}"
	steps:
	- uses: actions/checkout@v2
	- uses: actions/setup-python@v2
	with:
	python-version: '3.7'
	- name: Run docs precommit
	run: |
	cd ${MAGMA_ROOT}/docs
	make precommit

[hcgatewood]

cc @themarwhal

[themarwhal]

I made this required some time ago :)