[FEATURE] Update github templates to account for documentation updates

Is your feature request related to a problem?

The current github templates do not prompt the contributor to consider documentation implications.

What solution would you like?

I'd like to add a new field to each of the templates (Issue: Feature Request, Issue: Proposal, and PR), and that prompts an action by the contributor.

What alternatives have you considered?

We have steps in our internal processes to flag a feature for documentation, so we should have a similar flag when a contributor is entering a PR or Issue. This way, we are notified early that a change to documentation is coming, and we can determine scope and assign the appropriate resources.

Do you have any additional context?

For the Issue: Feature Request and Issue: Proposal templates:

Does the feature require updates to the documentation?
If yes, create a documentation issue with the following information: a summary of the proposed update, the target version, all versions that are affected, and other helpful details or links.

For the PR template:

Does the change require updates to the documentation?
If yes, add the “needs-documentation” label and provide the documentation PR link. If a PR doesn’t exist yet, add a link to the documentation issue.