.github - add pytorch dev infra team as codeowner (pytorch#78134)

@pytorch/pytorch-dev-infra should be a codeowner, to my understanding.

Trigger for this: we should get tagged on XLA PRs.
Pull Request resolved: pytorch#78134
Approved by: https://github.com/osalpekar, https://github.com/seemethere

CODEOWNERS

@@ -46,7 +46,7 @@
 # Github Actions
 # This list is for people wanting to be notified every time there's a change
 # related to Github Actions
-/.github/ @seemethere @janeyx99 @atalman
+/.github/ @pytorch/pytorch-dev-infra
 
 # Custom Test Infrastructure
 /test/run_test.py @pytorch/pytorch-dev-infra