[CI] Bump GH Actions OS versions

Summary:
Bump Ubuntu-based workflows to ubuntu-22.04 from ubuntu-latest (which is ubuntu-20.04). The newer ubuntu-22.04 image comes with the version of shellcheck (0.8.0) that we want.. which will prevent the GH Actions workflow from failing. Bumped the other Ubuntu workflows as well to maintain consistency (suggested by @abosh)

While at it, bumping macOS version from macos-latest (which is macos-11) to macos-12.

Test Plan: See what happens

Reviewers: abosh, varun, tomek, jacek

Reviewed By: abosh, varun

Subscribers: ashoat, adrian, abosh

Differential Revision: https://phab.comm.dev/D4827