Lower the lower dynamic buffer value to 1024

There's not a big performance difference between 8192 and 1024
so let's use less memory at the start of the connection.

src/cowboy.erl

@@ -166,7 +166,7 @@ ensure_dynamic_buffer(TransOpts, #{dynamic_buffer := DynamicBuffer}) ->
 ensure_dynamic_buffer(TransOpts=#{socket_opts := SocketOpts}, _) ->
 	case proplists:get_value(buffer, SocketOpts, undefined) of
 		undefined ->
-			{TransOpts#{socket_opts => [{buffer, 8192}|SocketOpts]}, {8192, 131072}};
+			{TransOpts#{socket_opts => [{buffer, 1024}|SocketOpts]}, {1024, 131072}};
 		_ ->
 			{TransOpts, false}
 	end.