Run lint-staged on tests and example files

[diego3g]

What would you like to be added:

Run lint-staged in tests and example folder.

Why is this needed:

People have different editors and configuration and sometimes Prettier is messing with those files and Pull Requests get rejected because of style guide.

Is your enhancement request related to a problem? Please describe.

Not a problem itself, but there are a lot of PR's with linting problems.

Additional context

Maybe something like this solve the issue:

"lint-staged": {
  "lib/**/*.{ts,tsx}": [
    "eslint --fix",
    "prettier --write",
    "jest --bail --findRelatedTests"
  ],
  "__tests__/**/*.{ts,tsx}" : [
    "eslint --fix",
    "prettier --write"
  ],
  "example/**/*.{ts,tsx}" : [
    "eslint --fix",
    "prettier --write"
  ]
},

[italomlp]

I think that in some cases the configuration of the editor can change *.md files too (happened with me). So, I suggest adding a configuration in lint-staged to achieve this too.