Update README.md about regex syntax link

diff --git a/README.md b/README.md
index 87226eba3043652fca432c2feb34f7a344738542..b04aaed068135a78fd666a66bbb70a78bbbaeeac 100644 (file)
--- a/README.md
+++ b/README.md
@@ -96,7 +96,7 @@ for the output text, and the color will be left unspecified (usually defaulting
 to white).
 
 For a reference of what kind of regex is supported,
-[see this page](https://docs.rs/regex/1.6.0/regex/index.html#syntax).
+[see this page](https://docs.rs/regex/1.9.1/regex/index.html#syntax).
 
 ## Net graph