chore(package): update standard-version to version 8.0.0

Closes #10

Author: greenkeeper[bot]

package.json

@@ -29,7 +29,7 @@
     "coveralls": "^3.0.2",
     "husky": "^1.2.0",
     "nyc": "^13.1.0",
-    "standard-version": "^5.0.0",
+    "standard-version": "^8.0.0",
     "xo": "^0.23.0"
   },
   "xo": {