remove prop types (#1138)

src/docs/frontend/index.mdx

@@ -68,23 +68,6 @@ Both the `app/components/` and `app/views` folders contain React components.
 - Use a view for UI that will typically not be reused in other parts of the codebase
 - Use a component for UI that is designed to be highly reusable.
 
-### PropTypes
-
-Use them, be explicit, use the shared custom proptypes when possible.
-
-Prefer `Proptypes.arrayOf` to `PropTypes.array` and `PropTypes.shape` to `PropTypes.object`
-
-If you’re passing Objects with an important, well defined set of keys (that your component relies on) then define them explicitly with `PropTypes.shape`:
-
-```javascript
-PropTypes.shape({
-  username: PropTypes.string.isRequired,
-  email: PropTypes.string
-})
-```
-
-If you’re re-using a custom prop-type or passing around a common shared shape like an organization, project, or user, then be sure to import a proptype from our useful collection of custom ones! [https://github.com/getsentry/sentry/blob/master/static/app/sentryTypes.tsx](https://github.com/getsentry/sentry/blob/master/static/app/sentryTypes.tsx)
-
 ### Event handlers
 
 We use different prefixes to better distinguish event handlers from event callback props.