Add pre-commit hooks

[dB2510]

What type of PR is this?
Feature

What does this PR do? Why is it needed?
Enables pre-commit git hooks which execute specific commands before each commit. This feature streamlines the development process by catching and fixing common issues, such as import errors and formatting problems, early on.

Other notes for review
To enable this feature, first we need to install pre-commit cli:

pip install pre-commit

Then install pre-commit hooks for prysm repo:

cd /PATH/TO/PRYSM
pre-commit install

The above commands are only run once while installing. After this, these git hooks will run everytime you commit.

Acknowledgements

• I have read CONTRIBUTING.md.
• I have included a uniquely named changelog fragment file.
• I have added a description to this PR with sufficient context for reviewers to understand this PR.