deps: bump regex-syntax to 0.5.1

Author: BurntSushi

Cargo.toml

@@ -30,7 +30,7 @@ memchr = "2.0.0"
 # For managing regex caches quickly across multiple threads.
 thread_local = "0.3.2"
 # For parsing regular expressions.
-regex-syntax = { path = "regex-syntax", version = "0.5.0" }
+regex-syntax = { path = "regex-syntax", version = "0.5.1" }
 # For accelerating text search.
 simd = { version = "0.2.1", optional = true }
 # For compiling UTF-8 decoding into automata.