GitHub Action for merging main into release branches is failing

[phargogh]

I just noticed this in the past couple of merges onto main, but here's a recent example of the build failure. From the logs, the issue appears to be that the hub cli has been deprecated in favor of gh and is no longer present on the runners.

++ git log -1 --pretty=%B main
++ egrep -o '#[1-9][0-9]*'
++ sed 's|#||g'
++ head -n1
+ PR_NUM=1441
++ hub pr show -f %au 1441
/home/runner/work/_temp/ecdccf6f-5f84-4f7b-80e7-24178a0ba015.sh: line 9: hub: command not found