fix(package): mv uglify2 to dependencies && update peerDependencies (#45)

Author: jharris4

package.json

@@ -55,11 +55,11 @@
   },
   "homepage": "https://github.com/webpack-contrib/uglifyjs-webpack-plugin",
   "peerDependencies": {
-    "uglify-js": "^2.8.0",
-    "webpack": "^2.0.0 || >= 3.0.0-rc.0 || ^3.0.0"
+    "webpack": "^1.9 || ^2 || ^2.1.0-beta || ^2.2.0-rc || ^3.0.0"
   },
   "dependencies": {
     "source-map": "^0.5.6",
+    "uglify-js": "^2.8.29",
     "webpack-sources": "^1.0.1"
   },
   "devDependencies": {
@@ -105,4 +105,4 @@
       "git add"
     ]
   }
-}
+}