fix: support capitalized github keywords

[AndersDJohnson]

Description

This PR adds case-insensitivity to the regular expression that looks for GitHub keywords (Close(s), Fix(es), Resolve(s)) in PR descriptions.

Motivation and Context

I noticed (I think) that we were possibly missing detection of capitalized GitHub keywords (Close(s), Fix(es), Resolve(s)). This is supported by GitHub so we should support it.

How Has This Been Tested?

• unit tests?

❌ Failing before:

✅ Passing after:

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Chore (updating repository quality of life, like deps, linting, etc.)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.

[therynamo]

EZ