Update codeowners and relevant workflows

[Polber]

This will help auto-assign reviewers to core templates infra, with reviews for individual templates being left to author to decide.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 45.09%. Comparing base (babf762) to head (b34bd74). Report is 246 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #1715      +/-   ##
============================================
+ Coverage     45.04%   45.09%   +0.05%     
- Complexity     3601     3934     +333     
============================================
  Files           835      835              
  Lines         49684    49693       +9     
  Branches       5229     5230       +1     
============================================
+ Hits          22378    22408      +30     
+ Misses        25639    25620      -19     
+ Partials       1667     1665       -2     

Components	Coverage Δ
spanner-templates	66.26% <50.00%> (+0.13%)	:arrow_up:
spanner-import-export	64.22% <50.00%> (+0.40%)	:arrow_up:
spanner-live-forward-migration	76.18% <ø> (ø)
spanner-live-reverse-replication	76.54% <ø> (ø)
spanner-bulk-migration	85.55% <ø> (ø)

see 5 files with indirect coverage changes

:rocket: New features to boost your workflow:

• :snowflake: Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• :package: JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[github-actions[bot]]

This pull request has been marked as stale due to 180 days of inactivity. It will be closed in 1 week if no further activity occurs. If you think that’s incorrect or this pull request requires a review, please simply write any comment. If closed, you can revive the PR at any time. Thank you for your contributions.

[github-actions[bot]]

This pull request has been closed due to lack of activity. If you think that is incorrect, or the pull request requires review, you can revive the PR at any time.