[repo] Add linting of yml/yaml files in CI

[CodeBlanch]

We ran into an issue where a typo in a yml file (09cafa5) broke all code coverage upload.

I did a quick scan of GitHub marketplace, there seem to be some YML linters available. We should add linting of yml/yaml files into the CI.

High level we need to add a bucket for these files here:

opentelemetry-dotnet-contrib/.github/workflows/ci.yml

Line 20 in dc7be37

md: [ '**.md' ]

yml: [ '**.yml, '**.yaml' ]

And then add a step for yml changes which calls some workflow to run linting. Similar to this...

opentelemetry-dotnet-contrib/.github/workflows/ci.yml

Lines 78 to 83 in dc7be37

	lint-md:
	needs: detect-changes
	if: |
	contains(needs.detect-changes.outputs.changes, 'md')
	|| contains(needs.detect-changes.outputs.changes, 'build')
	uses: ./.github/workflows/markdownlint.yml

[mowies]

Hi!
I'd like to work on this :)
Any recommendations on what YAML linter to use here? Otherwise i'll look through some other OTel repos and check out what they are using.

[CodeBlanch]

Thanks @mowies I assigned the issue to you. I have no idea what to use 🤣 Checking the other repos around OTel sounds like a great idea to me.