- Rename use of "preinstall" to "auto update". The original "preinstall"
naming came from the fact that we used to only auto-update before
`brew install` but now that it's many commands: this is more confusing
than useful.
- Add `HOMEBREW_NO_UPDATE_REPORT_ONLY_INSTALLED` and remove
`HOMEBREW_UPDATE_REPORT_ONLY_INSTALLED`; the latter is now the default
and the prior provides an opt-out for better output, performance and
avoiding reading potentially untrusted formulae.
- Add `HOMEBREW_UPDATE_FORMULA_VERSION_CHECKS` and don't check formula
versions by default for better performance by default.
Co-authored-by: Eric Knibbe <3324775+EricFromCanada@users.noreply.github.com>
Co-authored-by: Sam Ford <1584702+samford@users.noreply.github.com>
