Add GitHub to known instances (#397)

Author: zkoppert

patterns/2-structured/30-day-warranty.md

@@ -46,7 +46,8 @@ In addition it helps to provide clear [contribution guidelines](./project-setup/
 
 ## Known Instances
 
-This was tried and proven successful at PayPal.
+- This was tried and proven successful at PayPal.
+- GitHub internally uses this pattern with a modified warranty timeline of 6 weeks.
 
 ## Authors