Fix broken sponsor images (#951)

Removes links which are not required from Sponsors section

README.md

@@ -71,14 +71,6 @@ Support this project by becoming a sponsor. Your logo will show up here with a l
 
 <a href="https://opencollective.com/Docusaurus/sponsor/0/website" target="_blank"><img src="https://opencollective.com/Docusaurus/sponsor/0/avatar.svg"></a>
 <a href="https://opencollective.com/Docusaurus/sponsor/1/website" target="_blank"><img src="https://opencollective.com/Docusaurus/sponsor/1/avatar.svg"></a>
-<a href="https://opencollective.com/Docusaurus/sponsor/2/website" target="_blank"><img src="https://opencollective.com/Docusaurus/sponsor/2/avatar.svg"></a>
-<a href="https://opencollective.com/Docusaurus/sponsor/3/website" target="_blank"><img src="https://opencollective.com/Docusaurus/sponsor/3/avatar.svg"></a>
-<a href="https://opencollective.com/Docusaurus/sponsor/4/website" target="_blank"><img src="https://opencollective.com/Docusaurus/sponsor/4/avatar.svg"></a>
-<a href="https://opencollective.com/Docusaurus/sponsor/5/website" target="_blank"><img src="https://opencollective.com/Docusaurus/sponsor/5/avatar.svg"></a>
-<a href="https://opencollective.com/Docusaurus/sponsor/6/website" target="_blank"><img src="https://opencollective.com/Docusaurus/sponsor/6/avatar.svg"></a>
-<a href="https://opencollective.com/Docusaurus/sponsor/7/website" target="_blank"><img src="https://opencollective.com/Docusaurus/sponsor/7/avatar.svg"></a>
-<a href="https://opencollective.com/Docusaurus/sponsor/8/website" target="_blank"><img src="https://opencollective.com/Docusaurus/sponsor/8/avatar.svg"></a>
-<a href="https://opencollective.com/Docusaurus/sponsor/9/website" target="_blank"><img src="https://opencollective.com/Docusaurus/sponsor/9/avatar.svg"></a>