fix: resolve Elixir 1.20 compilation warnings

Author: gilbertwong96

.tool-versions

@@ -0,0 +1,2 @@
+elixir 1.20.0-rc.6
+erlang 27.3.3

lib/plug/router/utils.ex

@@ -151,15 +151,15 @@ defmodule Plug.Router.Utils do
       [{prefix_size, match_length}] when match_length == 2 ->
         suffix_size = byte_size(segment) - prefix_size - 2
 
-        <<prefix::binary-size(^prefix_size), ?\\, char, suffix::binary-size(^suffix_size)>> =
+        <<prefix::binary-^size(prefix_size), ?\\, char, suffix::binary-^size(suffix_size)>> =
           segment
 
         escaped_segment = [prefix <> <<char>> <> suffix | match]
         build_path_clause(rest, params, escaped_segment, guards, post_match, context, compiled)
 
       [{prefix_size, _}] ->
         suffix_size = byte_size(segment) - prefix_size - 1
-        <<prefix::binary-size(^prefix_size), char, suffix::binary-size(^suffix_size)>> = segment
+        <<prefix::binary-^size(prefix_size), char, suffix::binary-^size(suffix_size)>> = segment
         {param, suffix} = parse_suffix(suffix)
         params = [param | params]
         var = Macro.var(String.to_atom(param), context)