This commit fixes an issue with the ng-dev tool, where Github's API returns
paginated branch data. Only 30 branches are returned by default, and Angular
now has more than 30 branches in its repo. This commit increases the number
of branches returned to the API limit of 100, which should buy us some time
until we can implement proper pagination.
PR Close#42658
We initially added logic for determining active release trains into
the merge script. Given we now build more tools that rely on this
information, we move the logic into a more general "versioning" folder
that can contain common logic following the versioning document for the
Angular organization.
PR Close#38656
