Allow ! in url()s (#650)

Closes #646

CHANGELOG.md

@@ -1,4 +1,6 @@
-## 1.18.1
+## 1.19.0
+
+* Allow `!` in `url()`s without quotes.
 
 ### Dart API
 

lib/src/parse/stylesheet.dart

@@ -2621,7 +2621,8 @@ relase. For details, see http://bit.ly/moz-document.
       var next = scanner.peekChar();
       if (next == null) {
         break;
-      } else if (next == $percent ||
+      } else if (next == $exclamation ||
+          next == $percent ||
           next == $ampersand ||
           (next >= $asterisk && next <= $tilde) ||
           next >= 0x0080) {

pubspec.yaml

@@ -1,5 +1,5 @@
 name: sass
-version: 1.18.1-dev
+version: 1.19.0
 description: A Sass implementation in Dart.
 author: Dart Team <misc@dartlang.org>
 homepage: https://github.com/sass/dart-sass