Improve testing for pre-commit hooks

Figure out a way to test the pre-commit hooks in the actions.

Currently, the content of the hooks are tested with pytest, but I have to test my hook changes locally by updating the .pre-commit-config.yaml file:

```
- repo: local
hooks:
- id: add-license-headers
name: "Add License Headers"
entry: add-license-headers
language: python
files: '(src|examples|tests)/.*\.(py)|\.(proto)'
require_serial: true
args:
- --start_year=2023
exclude: |
(?x)^(
tests/test_add_license_headers_files/bad_chars.py |
tests/test_add_license_headers_files/index_error.scss
)$
```

**Next steps**
- Look at how hooks are tested in the [pre-commit repository](https://github.com/pre-commit/pre-commit) & do something similar?
- Create dummy repos for each hook that tests all scenarios for add-license-headers and tech-review respectively