Bump write-pkg module (#7)

OmgImAlexis · sindresorhus · commit 970d6fb7534a · 2017-07-10T20:49:01.000+02:00
diff --git a/package.json b/package.json
@@ -36,7 +36,7 @@
     "execa": "^0.5.0",
     "has-yarn": "^1.0.0",
     "read-pkg-up": "^2.0.0",
-    "write-pkg": "^2.0.0"
+    "write-pkg": "^3.1.0"
   },
   "devDependencies": {
     "ava": "*",
