Allow working with older PHF versions.

Author: emilio

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "cssparser"
-version = "0.29.5"
+version = "0.29.6"
 authors = [ "Simon Sapin <simon.sapin@exyr.org>" ]
 
 description = "Rust implementation of CSS Syntax Level 3"
@@ -24,7 +24,7 @@ cssparser-macros = {path = "./macros", version = "0.6"}
 dtoa-short = "0.3"
 itoa = "1.0"
 matches = "0.1"
-phf = {version = "0.10", features = ["macros"]}
+phf = {version = ">=0.8,<=0.10", features = ["macros"]}
 serde = {version = "1.0", optional = true}
 smallvec = "1.0"