chore(package): update gulp-bump to version 3.1.0

Closes #28

Author: greenkeeper[bot]

package.json

@@ -34,7 +34,7 @@
   },
   "devDependencies": {
     "gulp": "^3.9.0",
-    "gulp-bump": "^2.5.0",
+    "gulp-bump": "^3.1.0",
     "gulp-filter": "^5.0.0",
     "gulp-git": "^2.4.0",
     "gulp-tag-version": "^1.3.0",