Update dev-dependencies

Author: wooorm

Diff for: package.json

@@ -28,14 +28,14 @@
   "devDependencies": {
     "browserify": "^16.0.0",
     "json-stringify-safe": "^5.0.1",
-    "nyc": "^12.0.0",
+    "nyc": "^13.0.0",
     "parse5": "^5.0.0",
     "prettier": "^1.13.5",
-    "remark-cli": "^5.0.0",
+    "remark-cli": "^6.0.0",
     "remark-preset-wooorm": "^4.0.0",
     "tape": "^4.0.0",
     "tinyify": "^2.4.3",
-    "xo": "^0.21.0"
+    "xo": "^0.23.0"
   },
   "scripts": {
     "format": "remark . -qfo && prettier --write '**/*.js' && xo --fix",