Add release-checklist issue template

[iameskild]

Related to nebari-dev/governance#2

Please remove anything marked as optional that you don't need to fill in.
Choose one of the keywords preceding to refer to the issue this PR solves, followed by the issue number (e.g Fixes # 666).
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Changes introduced in this PR:

• Enables maintainers to easily create a release checklist that can guide them through the release process.

Types of changes

What types of changes does your PR introduce?

Put an x in the boxes that apply

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds a feature)
• Breaking change (fix or feature that would cause existing features to not work as expected)
• Documentation Update
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no API changes)
• Build related changes
• Other (please describe):

Testing

Requires testing

• Yes
• No

In case you checked yes, did you write tests?

• Yes
• No

Documentation

Does your contribution include breaking changes or deprecations?
If so have you updated the documentation?

• Yes, docstrings
• Yes, main documentation
• Yes, deprecation notices

Further comments (optional)

If this is a relatively large or complex change, kick off the discussion by explaining why you chose the solution you did and what alternatives you considered and more.

[trallard]

LGTM - except for the redundancy on having "two" release checklists - need to agree on a single source of truth

[iameskild]

Hi @trallard I've added the testing checklist issue template and updated the docs to point to reference these checklist templates. Let me know if you have any other feedback :)

[trallard]

LGTM 🚀