fix(site): Add rel="noopener nofollow" for links to sponsor websites (#2688)

* improvement: Add rel="noopener" for links to sponsor websites.

(https://mathiasbynens.github.io/rel-noopener/)

* improvement: add rel="nofollow" for links to sponsor websites, in order to discourage spam

Author: joealcorn

src/components/Support/Support.jsx

@@ -122,6 +122,7 @@ export default class Support extends React.Component {
                className="support__item"
                title={ `$${formatMoney(supporter.totalDonations / 100)} by ${supporter.name || supporter.slug}` }
                target="_blank"
+               rel="noopener nofollow"
                href={ supporter.website || `https://opencollective.com/${supporter.slug}` }>
               {<img
                 className={ `support__${rank}-avatar` }