* Improve getting started Coder CTA
This wasn't very standout-ish before, and I think it's
wise for us to experiment with directing users to Coder.
* Update nix flake
* Update diff
* Add advert to code-server install
* Fix patch to reset columns if getting started is disabled
* Update text for advert
feat(script): add steps-lib, is_env_var_set & test
feat(brew-bump): add check for VERSION
feat(brew-bump): check HOMEBREW_GITHUB_API_TOKEN
feat(steps-lib): add directory_exists helper fn
fix(brew-bump): check that git clone worked
feat(brew-bump): add check for remote upstream
fix: remove upstream command thing
feat(steps-lib): add file_exists helper function
feat(brew-bump): add check for git-askpass.sh
feat(steps-lib): add is_executable function & test
feat(brew-bump): add check for is_executable
refactor: use GIT_ASKPASS as variable
