Fix typo: Dubbo instead of Thrift (#5322)

*Description*: Fix typo in dubbo proxy proto comment.
*Risk Level*: Low
*Testing*: N/A
*Docs Changes*: N/A
*Release Notes*: N/A

Signed-off-by: Dhi Aurrahman <dio@tetrate.io>

Mirrored from https://github.com/envoyproxy/envoy @ ab127e10f596f905fe1c88cba72f83340af85cb9

envoy/config/filter/network/dubbo_proxy/v2alpha1/dubbo_proxy.proto

@@ -5,8 +5,9 @@ option go_package = "v2";
 
 import "validate/validate.proto";
 
-// [#protodoc-title: Extensions Thrift Proxy]
+// [#protodoc-title: Dubbo Proxy]
-// Thrift Proxy filter configuration.
+// Dubbo Proxy filter configuration.
+
 message DubboProxy {
   // The human readable prefix to use when emitting statistics.
   string stat_prefix = 1 [(validate.rules).string.min_bytes = 1];