Setup a GH action for congratulating contributor when a PR is merged

[jdwilkin4]

Whenever a contributor has a PR approved and merged there should an automated message left on the closed PR congratulating them on their good work.

If they are a first time contributor, then we will want to modify the message to acknowledge that.

Lastly, we will want to look into having the message come from an actual account like starter.dev instead of it saying GH actions bot here

Acceptance criteria

• [x] create a custom congrats message that will be shown when a PR is approved and merged
• [x] conditional render a message for first time contributors vs returning contributors
• [x] set the message to come from the repo owner instead of GH actions bot
• [x] the PAT will expire every 90 days so add a condition in the script to account for that