Maintainer application (#640)

I'm a maintainer of several other services often related to the Kuberenetes back-end/Kubernetes controllers and I'm taking ownership for a lot of release synchronization making it both appropriate and necessary for me to maintain aspects of the Tink repository.

Requirements:

- I have reviewed the [community membership guidelines](https://github.com/tinkerbell/proposals/blob/main/proposals/0024/GOVERNANCE.md)
- I have [enabled 2FA on my GitHub account](https://github.com/settings/security)
- I have subscribed to the [tinkerbell-contributors e-mail list](https://groups.google.com/g/tinkerbell-contributors)
- I am actively contributing to 1 or more Tinkerbell subprojects

Here is a list of non-trival PRs I have been the primary reviewer on:

#596
#628
#614

I have also made a number of code contributions to this repository, here are a few of them:

#638
#631
#626
#622
#612

I have also raised various issues and am driving the releasing across Tinkerbell including in this repository.

Requesting consideration of expedited responsibilities: yes

Sponsors:

- @mmlb (Maintainer)
- @micahhausler (Maintainer)
- @jacobweinstock (Core contributor in other Tinkerbell repositories)

.github/CODEOWNERS

@@ -1,2 +1,2 @@
-/.github/settings.yml @mmlb @micahhausler
-/.github/CODEOWNERS @mmlb @micahhausler
+/.github/settings.yml @mmlb @micahhausler @chrisdoherty4
+/.github/CODEOWNERS @mmlb @micahhausler @chrisdoherty4

.github/settings.yml

@@ -6,6 +6,8 @@ collaborators:
     permission: maintain
   - username: mmlb
     permission: maintain
+  - username: chrisdoherty4
+    permission: maintain
   # Approvers
   - username: displague
     permission: push
@@ -16,8 +18,6 @@ collaborators:
   - username: tstromberg
     permission: push
   # Reviewers
-  - username: chrisdoherty4
-    permission: triage
   - username: detiber
     permission: triage
   - username: stephen-fox