Updating pubspec.yaml with a new version of font_face_observer 2.0.0

Author: Rosie the Robot

pubspec.yaml

@@ -1,5 +1,5 @@
 name: 'font_face_observer'
-version: 1.1.1
+version: 2.0.0
 description: Font load events, simple, small and efficient. Dart port of https://github.com/bramstein/fontfaceobserver
 author: Rob Becker <rob.becker@workiva.com>
 homepage: https://github.com/Workiva/font_face_observer