Ratelimit: Add optional descriptor key to generic_key action (#12734)

Signed-off-by: Clara Andrew-Wani <candrewwani@gmail.com>

Mirrored from https://github.com/envoyproxy/envoy @ a944559ba059d5ebe964dfbbd76b9d293dcce3dc

envoy/config/route/v3/route_components.proto

@@ -1546,6 +1546,10 @@ message RateLimit {
 
       // The value to use in the descriptor entry.
       string descriptor_value = 1 [(validate.rules).string = {min_bytes: 1}];
+
+      // An optional key to use in the descriptor entry. If not set it defaults
+      // to 'generic_key' as the descriptor key.
+      string descriptor_key = 2;
     }
 
     // The following descriptor entry is appended to the descriptor:

envoy/config/route/v4alpha/route_components.proto

@@ -1531,6 +1531,10 @@ message RateLimit {
 
       // The value to use in the descriptor entry.
       string descriptor_value = 1 [(validate.rules).string = {min_bytes: 1}];
+
+      // An optional key to use in the descriptor entry. If not set it defaults
+      // to 'generic_key' as the descriptor key.
+      string descriptor_key = 2;
     }
 
     // The following descriptor entry is appended to the descriptor: