Update dev-dependencies

Author: wooorm

package.json

@@ -35,10 +35,10 @@
     "babelify": "^8.0.0",
     "browserify": "^16.0.0",
     "esmangle": "^1.0.0",
-    "hastscript": "^3.0.1",
+    "hastscript": "^4.0.0",
     "nyc": "^12.0.0",
     "prettier": "^1.13.5",
-    "rehype-stringify": "^3.0.0",
+    "rehype-stringify": "^4.0.0",
     "remark-cli": "^5.0.0",
     "remark-parse": "^5.0.0",
     "remark-preset-wooorm": "^4.0.0",