ci: another fixup round for api_mirror.sh. (#3090)

Validated the full push-to-master to data-plane-api, so this time it should work.

Signed-off-by: Harvey Tuch <htuch@google.com>

Mirrored from https://github.com/envoyproxy/envoy @ bf1073f04db95b674575c9f96fc821a5537774b2

envoy/admin/v2/config_dump.proto

@@ -18,7 +18,7 @@ import "gogoproto/gogo.proto";
 message ConfigDump {
   // This map is serialized and dumped in its entirety at the /config_dump endpoint.
   //
-  // Keys should be a short descriptor of the config object they map to. For example, envoy's HTTP
+  // Keys should be a short descriptor of the config object they map to. For example, Envoy's HTTP
   // routing subsystem might use "routes" as the key for its config, for which it uses the message
   // RouteConfigDump as defined below. In the future, the key will also be used to filter the output
   // of the /config_dump endpoint.