Check for git directory before pre-commit

[pamelafox]

Purpose

Fixes #2

As of a week ago, dev containers have started throwing errors for calling pre-commit install when not in a git repository. This hopefully fixes it, since it checks for .git directory before calling pre-commit.

Does this introduce a breaking change?

[ ] Yes
[X] No

Pull Request Type

What kind of change does this Pull Request introduce?

[X] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Documentation content changes
[ ] Other... Please describe: