Make form_urlencoded no_std compatible

See SimonSapin/rust-std-candidates#23 for the `matches` version bump.

Author: madsmtm

form_urlencoded/Cargo.toml

@@ -11,5 +11,5 @@ edition = "2018"
 test = false
 
 [dependencies]
-matches = "0.1"
+matches = "0.1.9"
 percent-encoding = { version = "2.1.0", path = "../percent_encoding" }

form_urlencoded/src/lib.rs

@@ -13,12 +13,18 @@
 //! Converts between a string (such as an URL’s query string)
 //! and a sequence of (name, value) pairs.
 
+#![no_std]
+extern crate alloc;
+
 #[macro_use]
 extern crate matches;
 
+use alloc::{
+    borrow::{Borrow, Cow, ToOwned},
+    string::String,
+};
+use core::str;
 use percent_encoding::{percent_decode, percent_encode_byte};
-use std::borrow::{Borrow, Cow};
-use std::str;
 
 /// Convert a byte string in the `application/x-www-form-urlencoded` syntax
 /// into a iterator of (name, value) pairs.