This removes the dependency on shared libmonosgen installed locally
and makes the artifacts usable as standalone for testing without
needing a full Mono install.
This will enforce that PRs properly sync the class reference templates to match
their changes to the public API, and help notice binding bugs in the process
(e.g. missing enum bindings, unexpected API changes or missing argument names).
This should also serve as a reminder to contributors that their changes impact
the scripting API and might warrant actually filling the descriptions for the
new methods/properties/etc.
This was forgotten when renaming 3.2.4 to 3.3.
Once 3.3-stable is out and we branch off to 3.3, the BASE_BRANCH should
be bumped to 3.3 in that branch.
We often hit "Too Many Requests" errors when uploading the cache with
`actions/cache` because there's a limit of 10 GB every 5 minutes, and we can
easily go over it when we amend or merge several PRs in a short timespan.
This will make the CI artifacts less useful for debugging crashes but there's
no real way around this.
(cherry picked from commit caea551d41)
Removes AppVeyor and all Travis jobs but the iOS one, which hasn't been ported
to GitHub Actions yet (should be done soon).
Backports new style scripts from `master` branch too to do the same checks.
