config: removing deprecated_v1 from the HCM config (#4843)

This makes marking filters as encoder/decoder/both illegal.

Risk Level: Medium (breaking change for old configs)
Testing: existing tests pass including legacy json tests (with modified config)
Docs Changes: No
Release Notes: Not currently

Signed-off-by: Alyssa Wilk <alyssar@chromium.org>

Mirrored from https://github.com/envoyproxy/envoy @ dcb4f39ba103062472f4f94f3f39c4900750763f

envoy/config/filter/network/http_connection_manager/v2/http_connection_manager.proto

@@ -397,13 +397,5 @@ message HttpFilter {
   // instantiated. See the supported filters for further documentation.
   google.protobuf.Struct config = 2;
 
-  // [#not-implemented-hide:]
-  // This is hidden as type has been deprecated and is no longer required.
-  message DeprecatedV1 {
-    string type = 1;
-  }
-
-  // [#not-implemented-hide:]
-  // This is hidden as type has been deprecated and is no longer required.
-  DeprecatedV1 deprecated_v1 = 3 [deprecated = true];
+  reserved 3;
 }