update dependencies (#2770)

- acorn@5.3.0
- commander@2.13.0

package.json

@@ -9,15 +9,10 @@
     "node": ">=0.8.0"
   },
   "maintainers": [
+    "Alex Lam <alexlamsl@gmail.com>",
     "Mihai Bazon <mihai.bazon@gmail.com> (http://lisperator.net/)"
   ],
-  "repository": {
-    "type": "git",
-    "url": "https://github.com/mishoo/UglifyJS2.git"
-  },
-  "bugs": {
-    "url": "https://github.com/mishoo/UglifyJS2/issues"
-  },
+  "repository": "mishoo/UglifyJS2",
   "main": "tools/node.js",
   "bin": {
     "uglifyjs": "bin/uglifyjs"
@@ -29,11 +24,11 @@
     "LICENSE"
   ],
   "dependencies": {
-    "commander": "~2.12.1",
+    "commander": "~2.13.0",
     "source-map": "~0.6.1"
   },
   "devDependencies": {
-    "acorn": "~5.2.1",
+    "acorn": "~5.3.0",
     "mocha": "~3.5.1",
     "semver": "~5.4.1"
   },