ci: Add codeowners file to finch

[vsiravar]

Issue #, if available:
N/A.
Description of changes:

• Add CODEOWNERS file to finch to ensure that release-please PR which modifies CHANGELOG.md has to be reviewed and approved by a member of @runfinch/dev-team in order to kick off a finch release.
• Ensures that any changes to .github directory requires approval from @runfinch/dev-team, i.e even modifications to CODEOWNERS would require an approval from the team.
• Modifies ci.yaml to not run CI checks on CODEOWNERS file.

Testing done:
Yes, on personal repo.
See code owners setting in CODEOWNERS and test requesting review from code owner

• I've reviewed the guidance in CONTRIBUTING.md

License Acceptance

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[weikequ]

Hey, sorry for getting to this a bit late, but you will also need to add the opposite entry to ci-docs.yaml, or else our PRs will get blocked (as they require those tests to be run, but have no way to run them).

[vsiravar]

Hey, sorry for getting to this a bit late, but you will also need to add the opposite entry to ci-docs.yaml, or else our PRs will get blocked (as they require those tests to be run, but have no way to run them).

:( had forgotten about this strangeness. Created PR for it. Good thing though, the CODEOWNERS check worked. Created PR to fix it. #502