[BUG] Fix Deserializing WorkflowJob

[lineville]

Resolves #2724 by making the following fields nullable: RunnerId, RunnerName, RunnerGroupId, RunnerGroupName which may be null when the WorkflowJob is coming from a WorkflowJobEvent webhook.

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Behavior

Before the change?

• Deserializing a WorkflowJob that was received from a WorkflowJobEvent webhook would fail if any of the non-nullable fields we're null.

After the change?

• Deserializing a WorkflowJob that was received from a WorkflowJobEvent webhook succeeds even if it has null values for the 4 fields mentioned above.

Other information

• See the webhooks.net/WorkflowJob model for reference of the model that this should map to.

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Additional info

Pull request checklist

• Tests for the changes have been added (for bug fixes / features)
• Docs have been reviewed and added / updated if needed (for bug fixes / features)
• Added the appropriate label for the given change

Does this introduce a breaking change?

Please see our docs on breaking changes to help!

• Yes (Please add the Type: Breaking change label)
• No

If Yes, what's the impact:

• N/A

Pull request type

Please add the corresponding label for change this PR introduces:

• Bugfix: Type: Bug
• Feature/model/API additions: Type: Feature
• Updates to docs or samples: Type: Documentation
• Dependencies/code cleanup: Type: Maintenance

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[kfcampbell]

Thank you @lineville!

[lineville]

@kfcampbell Any plans to cut a release anytime soon 😄 ? Is there a plan to try to land a few more PRs before cutting a release? Thanks again for the quick turn around approving and merging this! ♥️

[kfcampbell]

@lineville I've released v6.1.0; please let me know if your changes aren't properly reflected in that version.