Create Pull Request template

[DenisCarriere]

• [ ] Extend pull_request_template.md to include helpful information to add new chains & providers
  • [ ] Make a pull request
  • [ ] Common mistakes
  • [ ] Running tests
  • [ ] How to add a:
  • [ ] new chain
  • [ ] new provider
  • [ ] new block
  • [ ] new icon

Example of Pull Request templates

• https://github.com/sindresorhus/awesome/blob/main/pull_request_template.md
• https://github.com/DefinitelyTyped/DefinitelyTyped/blob/master/.github/PULL_REQUEST_TEMPLATE.md

Docs creating Pull Request template

• https://docs.github.com/en/communities/using-templates-to-encourage-useful-issues-and-pull-requests/creating-a-pull-request-template-for-your-repository