Add actionlint to prevent GHA workflow errors

[jni]

This adds actionlint from napari/napari#7049 to help prevent errors in GHA workflows.

Update: @Czaki also fixed the errors found by actionlint and ensured that new docs builds from tags (a) end up in their own folder (rather than dev/), and (b) don't include alpha, beta and rc tags.

[jni]

@Czaki, actionlint fails with errors in these lines:

docs/.github/workflows/build_and_deploy.yml

Lines 109 to 114 in ffc22d0

	run: |
	if [[ "${{ github.ref }}" == "refs/tags/"* ]]; then
	echo "branch_name=${{ github.ref_name }}" >> $GITHUB_ENV
	else
	echo "branch_name=dev" >> $GITHUB_ENV
	fi

.github/workflows/build_and_deploy.yml:109:9: shellcheck reported issue in this script: SC2193:warning:1:27: The arguments to this comparison can never be equal. Make sure your syntax is correct [shellcheck]

which explains why the deployment with 0.5.0 only happened in dev and didn't go into a folder. Do you have ideas on how to fix it?

[Czaki]

ealier code have 2 problems.

• it will put v0.5.1 as version instead of 0.5.0
• it will create folders for rc, alpha and beta.

I think that this code should work. We may test it by creating 0.5.1b1 and check if 0.5.0 is available (still may be not selectable from dropdown).