refactor all to async/await (#617)

Co-authored-by: Danny Browning <danny.browning@protectwise.com>
Co-authored-by: Daniel Eades <danieleades@hotmail.com>

src/into_url.rs

@@ -27,7 +27,7 @@ impl PolyfillTryInto for Url {
 
 impl<'a> PolyfillTryInto for &'a str {
     fn into_url(self) -> crate::Result<Url> {
-        try_!(Url::parse(self)).into_url()
+        Url::parse(self).map_err(crate::error::from)?.into_url()
     }
 }