Back-port GitHub Actions to ICU 68 (replaces Travis CI)
I'm filing a new ticket in order to back-port the GitHub Actions (GHA) script from master to maint/maint-68, as there are two prior tickets for the GHA migration.
I had to modify the GHA CI script to enable running on branches other than master.
There are two commits in PR .
I'll create another PR into master, as we'll want to enable running the GHA on other maint/maint-* branches (i.e.: for ICU 69) as well – so adjusting this ticket to have Fix versions of 68.2 and 69.1