Add null challenges #13

	name: Linter

	on: [pull_request]

	jobs:
	# markdown-linter:
	# name: "Markdown Linter"
	# runs-on: ubuntu-latest
	# steps:
	# - uses: actions/checkout@v2
	# - name: markdownlint-cli
	# uses: nosborn/[email protected]
	# with:
	# files: .
	# config_file: .markdownlint.yaml

	# markdown-link-check:
	# name: "Markdown Link Checker"
	# runs-on: ubuntu-latest
	# steps:
	# - uses: actions/checkout@v2
	# - uses: gaurav-nelson/[email protected]

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