codeowners file updates

Why these changes are being introduced:

This commit updates the codeowners file to match github recommended best
practices.

Side effects of this change:

None

Changes to be committed:
      modified:   .github/CODEOWNERS

Author: vab

.github/CODEOWNERS

@@ -1,7 +1,20 @@
-# CODEOWNERS file for mitlib-tf-workloads-ecr
+# CODEOWNERS file (from GitHub template at
+# https://docs.github.com/en/repositories/managing-your-repositorys-settings-and-features/customizing-your-repository/about-code-owners)
+# Each line is a file pattern followed by one or more owners.
 
 ################################################################################
-# This repository is maintained by the MIT Libraries Infrastructure Team.
+# These owners will be the default owners for everything in the repo. Unless a
+# later match takes precedence, @cabutlermit will be requested for review when 
+# someone opens a pull request.This is commented out in favor of using a team
+# as the default (see below). It is left here as a comment to indicate the
+# primary expert for this code.
+# * @cabutlermit
+
+# Teams can be specified as code owners as well. Teams should be identified in
+# the format @org/team-name. Teams must have explicit write access to the 
+# repository.
 * @mitlibraries/infraeng-terraform-reviewers
 
-# There are no individual code owners for this repository.
+# We set the senior engineer in the team as the owner of the CODEOWNERS file as
+# a layer of protection for unauthorized changes.
+/.github/CODEOWNERS @cabutlermit