Enable websocket compression compat date

This does not enable compression for all compatibility dates.

Author: MellowYarker

src/workerd/io/compatibility-date.capnp

@@ -224,7 +224,8 @@ struct CompatibilityFlags @0x8f8c1b68151b6cef {
   # Obsolete flag. Has no effect.
 
   webSocketCompression @20 :Bool
-      $compatEnableFlag("web_socket_compression");
+      $compatEnableFlag("web_socket_compression")
+      $compatEnableDate("2023-08-15");
   # Enables WebSocket compression. Without this flag, all attempts to negotiate compression will
   # be refused, so WebSockets will never use compression. With this flag, the system will
   # automatically negotiate the use of the permesssage-deflate extension where appropriate.