Update CREDITS

Add list of patreons.

CREDITS

@@ -158,3 +158,11 @@ Contributed X File exporter
 Contributed Step (stp) exporter
 
 For a more detailed list just check: https://github.com/assimp/assimp/network/members
+
+Patreons:
+- migenius
+- Marcus
+- Cort
+- elect
+- Steffen
+