lock babel-plugin-transform-regenerator dependency to fix #425

(cherry picked from commit 08c3285)

Author: sindresorhus

package.json

@@ -81,6 +81,7 @@
     "ava-init": "^0.1.0",
     "babel-core": "^6.3.21",
     "babel-plugin-espower": "^2.1.0",
+    "babel-plugin-transform-regenerator": "6.3.26",
     "babel-plugin-transform-runtime": "^6.3.13",
     "babel-preset-es2015": "^6.3.13",
     "babel-preset-stage-2": "^6.3.13",