Add config to ignore files listed in `.gitignore`

[jacobcassidy]

Problem

Currently, files ignored in .gitignore are still linted by this extension, which adds a lot of noise in VSCode.

Solution

Add a config to ignore all files listed in .gitignore or ignore those files by default.

Additional information

No response

👨‍👧‍👦 Contributing

• 🙋‍♂️ Yes, I'd love to make a PR to implement this feature!