Update changes.yml to exclude non-build/test yaml files

[willdavsmith]

Today, the changes.yml only checks markdown. We should update it to include yaml changes as well. We should still make the tests run on some yaml changes, such as the test workflows.

Here's an example of a PR where we shouldn't need to run functional tests: #11497

[radius-triage-bot]

👍 We've reviewed this issue and have agreed to add it to our backlog. Please subscribe to this issue for notifications, we'll provide updates when we pick it up.

We also welcome community contributions! If you would like to pick this item up sooner and submit a pull request, please visit our contribution guidelines and assign this to yourself by commenting "/assign" on this issue.

For more information on our triage process please visit our triage overview