Precommit linting checks non staged files.

[mcottontensor]

Component your feature request relates to

• Signalling server
• Frontend library
• Frontend UI library
• Matchmaker
• SFU
• This repo

Problem your feature solves? Please describe.
When committing the pre commit hook will run lint on the local repo which is good but you can end up in a situation where the changes that fix the linting errors are non staged and the commit will pass.

Describe the solution you'd like
Ideally the lint should only lint against the base changes plus the staged changes and ignore the unstaged changes. This will allow you to safely commit and know that the committed changes will pass linting on the GH side.

[mcottontensor]

This tool may handle it https://github.com/lint-staged/lint-staged