build: Add regenerator-runtime dependency

Author: tmcw

package.json

@@ -41,6 +41,7 @@
     "parse-filepath": "^1.0.1",
     "pify": "^3.0.0",
     "read-pkg-up": "^2.0.0",
+    "regenerator-runtime": "^0.10.5",
     "remark": "^8.0.0",
     "remark-html": "6.0.1",
     "remark-toc": "^4.0.0",