Update phf to 0.12

Author: xu-cheng

Cargo.toml

@@ -34,8 +34,8 @@ mac = "0.1"
 tendril = "0.4"
 string_cache = "0.8.8"
 string_cache_codegen = "0.5.4"
-phf = "0.11"
-phf_codegen = "0.11"
+phf = "0.12"
+phf_codegen = "0.12"
 
 # Dev dependencies
 criterion = "0.6"