Publish 0.4.0, identical to 0.2.38

… to work around rust-lang/crates.io#76

0.3.0 was published and then yanked:
#135 (comment)

Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 
 name = "url"
-version = "0.2.38"
+version = "0.4.0"
 authors = [ "Simon Sapin <simon.sapin@exyr.org>" ]
 
 description = "URL library for Rust, based on the WHATWG URL Standard"