chore(package): update atom-linter to version 7.0.0 (#124)

https://greenkeeper.io/

Author: greenkeeperio-bot

package.json

@@ -20,7 +20,7 @@
   },
   "dependencies": {
     "atomlinter-csslint": "0.10.0",
-    "atom-linter": "^6.0.0",
+    "atom-linter": "^7.0.0",
     "atom-package-deps": "^4.0.1"
   },
   "devDependencies": {