chore(package): update textlint to version 8.0.0

https://greenkeeper.io/

Author: greenkeeperio-bot

package.json

@@ -43,7 +43,7 @@
     "eslint-plugin-import": "^2.2.0",
     "mocha": "^3.2.0",
     "npm-run-all": "^4.0.1",
-    "textlint": "^7.2.1",
+    "textlint": "^8.0.0",
     "textlint-tester": "^2.1.0"
   }
 }