release v1.2.0

now when uglify errors, the error is captured and given the filename of
the src being parsed.

package.json

@@ -1,6 +1,6 @@
 {
   "name": "ember-cli-uglify",
-  "version": "1.0.1",
+  "version": "1.2.0",
   "description": "JavaScript minification for Ember-CLI",
   "scripts": {
     "start": "ember server",
@@ -23,6 +23,6 @@
     "before": "broccoli-asset-rev"
   },
   "dependencies": {
-    "broccoli-uglify-sourcemap": "^0.2.1"
+    "broccoli-uglify-sourcemap": "^1.0.0"
   }
 }