Surround360 open edition: remove broken website link

Summary: https://facebook360.fb.com/facebook-surround-360/ is temporarily down. We are in the process of updating the website. Deleting the link for now. Will put it back up when it's ready again.

Reviewed By: tox-fb

Differential Revision: D8000671

fbshipit-source-id: 04337f823f599e890377a05bf5acc13817138573

README.md

@@ -30,8 +30,6 @@ We provide a sample dataset for those who are interested in testing the renderin
 
 ## Join the Surround360 community
 
-* Website: https://facebook360.fb.com/facebook-surround-360/
-
 See the CONTRIBUTING file in each subdirectory for how to help out.
 
 ## License