Option to warn or error in pre-commit on the PPT version check

[drewoldag]

Currently the LF-PPT version check pre-commit hook will always pass, even if the template that a project uses is out of date.

Given that many people don't use pre-commit locally, but we run it as part of CI, we could allow users to choose error (and be "forced" to update to the latest version) or warn (that will simply produce the warning message).

Also, should we run pre-commit as part of smoke tests specifically for the reason called out?