Github Action to Validate Changelogs

[kevinpalis]

Description

This PR adds a GH actions to validate changelogs.
One of the pain points in Jenkins is that you need to look through the output logs to see what the error is. This is addressed here in two ways:

1. Everything runs in Github via actions and you won't need to VPN to access Jenkins
2. All the information on the validation errors are added by a bot as a comment to this PR, ie. no need to go through logs

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Checklist

If you can answer "yes" to the following items, please add a checkmark next to the appropriate checklist item(s) and notify our WARP documentation team by tagging either @ekiernan or @kayleemathews in a comment on this PR.

• Did you add inputs, outputs, or tasks to a workflow?
• Did you modify, delete or move: file paths, file names, input names, output names, or task names?
• If you made a changelog update, did you update the pipeline version number?

[github-actions]

Remember to squash merge!

[github-actions]

Remember to squash merge!

[github-actions]

Remember to squash merge!

[github-actions]

Remember to squash merge!

[github-actions]

Remember to squash merge!

[github-actions]

Remember to squash merge!

[github-actions]

Remember to squash merge!

[github-actions]

Remember to squash merge!

[github-actions]

Remember to squash merge!

[github-actions]

Remember to squash merge!

[github-actions]

Remember to squash merge!

[github-actions]

Validation Results:

Comparing versions and changelogs for pipelines that differ from the versions on 'origin/develop':
BuildIndices.wdl and BuildIndices.changelog.md do not have matching versions
Some WDLs or changelog files need updating. See output for details.

[github-actions]

Remember to squash merge!

[github-actions]

Validation Results:

[github-actions]

Remember to squash merge!

[github-actions]

Validation Results:

Comparing versions and changelogs for pipelines that differ from the versions on 'origin/develop':
BuildIndices.wdl and BuildIndices.changelog.md do not have matching versions
Some WDLs or changelog files need updating. See output for details.
validation_failed

[github-actions]

Remember to squash merge!

[github-actions]

Validation Results:

basename: missing operand
Try 'basename --help' for more information.
Comparing versions and changelogs for pipelines that differ from the versions on 'origin/develop':
All WDLs and changelog files appear to be valid for this release.