Add PR template

We have to be thorough when upgrading dependencies. In order to democratize this process, we should provide a clear contribution path for those (like me) who wish to help.

• Mention steps / requirements for dependency updates
• Provide a template for each added rule (e.g. following the same outline as below)

- **eslint-config-prettier:** [`v2.6.0...v2.9.0`](https://github.com/prettier/eslint-config-prettier/compare/v2.6.0...v2.9.0)
  - Added: The [implicit-arrow-linebreak] rule
  - Added: The [react/jsx-one-expression-per-line] rule.
  - Added: The [lines-around-comment] rule (as a [special
    rule][lines-around-comment-special]).
  - Added: The [no-unexpected-multiline] rule (as a [special
    rule][no-unexpected-multiline-special]).

• Require a changelog update
• For important/breaking changes: require the upgrade path to be documented

Do you see anything else? cc @GoodForOneFare @ismail-syed @lemonmade

[atesgoral]

@alexandcote Can this be closed with #181 or is there more work to be done?

[kaelig]

Thanks for the feedback, guys.

Regarding the upgrade path, it could be as simple as:

Does this not seem useful?

---

We’re going to merge this repo back into Shopify/javascript, and I think Github won’t handle folder-specific PR templates

I didn’t know about that. Thanks!

---

Are these for custom Shopify rules, or when we bump a dependency and add a new rule that was introduced?

@ismail-syed probably both?

I’ve edited the issue to show what it may look like