Use Sprocket GitHub Action in CI

[adthrasher]

Update the Sprocket lint in the workflow to use the public Sprocket GitHub Action.

PR checklist

• This comment contains a description of changes (with reason).
• If you've fixed a bug or added code that should be tested, add tests!
• Make sure your code validates (womtool validate or miniwdl check).
• Ensure the test suite passes.
• Documentation is updated.
• CHANGELOG.md is updated.
• .dockstore.yml is updated.
• README.md is updated.

[claymcleod]

I wonder if we should also update the PR checklist to include the code passing the sprocket lints?

[adthrasher]

@vsmalladi - I can't request a review from you, so tagging to make sure this isn't missed. We've published a GitHub Action to wrap Sprocket's check and lint functionality.

[vsmalladi]

LGTM

[vsmalladi]

Merge when ready.

[adthrasher]

@vsmalladi - I don't have permission to merge.