Framework: Ignore more transient directories for lint

[aduth]

This pull request seeks to include additional directories in .eslintignore to further align between this file and .gitignore. Without these changes, there can be significant time wasted recursing into folders not intended to be scanned for ESLint violations.

Testing Instructions:

Verify lint passes:

npm run lint-js

For good measure, you may also verify that an intentionally-introduced lint error fails as expected.

[gziolo]

Should we add any of those entries to the .eslintignore file used internally in @wordpress/scripts package https://github.com/WordPress/gutenberg/blob/master/packages/scripts/config/.eslintignore? Maybe .cache folder would make sense.

[aduth]

@gziolo I hadn't considered it. I guess it depends what criteria we use to include files for ignore there; should it be limited to files which might be introduced by other scripts in @wordpress/scripts? The .cache folder is unique to Parcel, not a standard folder we would expect to find in most projects.

[gziolo]

@gziolo I hadn't considered it. I guess it depends what criteria we use to include files for ignore there; should it be limited to files which might be introduced by other scripts in @wordpress/scripts? The .cache folder is unique to Parcel, not a standard folder we would expect to find in most projects.

I need to update https://github.com/WordPress/gutenberg-examples to fully use @wordpress/scripts package and this will let us find the answer :)