Use a 8-bit ansi palette for grey (#2474)

diff --git a/lib/src/log.dart b/lib/src/log.dart
index 893759c..35815b7 100644
--- a/lib/src/log.dart
+++ b/lib/src/log.dart
@@ -55,7 +55,7 @@
 final _red = getSpecial('\u001b[31m');
 final _yellow = getSpecial('\u001b[33m');
 final _blue = getSpecial('\u001b[34m');
-final _gray = getSpecial('\u001b[1;30m');
+final _gray = getSpecial('\u001b[38;5;245m');
 final _none = getSpecial('\u001b[0m');
 final _noColor = getSpecial('\u001b[39m');
 final _bold = getSpecial('\u001b[1m');