fix name

proto/collections/collections.proto

@@ -26,7 +26,7 @@ message Collection {
   optional bool no_data = 12;
   string schema = 7;
   bool hidden = 13;
-  google.protobuf.Duration TTL = 14;
+  google.protobuf.Duration ttl = 14;
 
   message View {
     string space_id = 1;