add note about AngularJS

Otherwise people may get confused by the name `angular-file-upload` as the "new" Angular gets called just "Angular" while the previous version has now the official name "AngularJS" :)

Author: juristr

README.md

@@ -1,5 +1,7 @@
 # Angular File Upload
 
+> compatible with AngularJS v1.x
+
 ---
 
 ## About