chore(package): update atom-linter to version 7.0.0 (#128)

https://greenkeeper.io/

Author: greenkeeperio-bot

package.json

@@ -44,7 +44,7 @@
   },
   "homepage": "https://github.com/AtomLinter/linter-htmlhint#readme",
   "dependencies": {
-    "atom-linter": "^6.0.0",
+    "atom-linter": "^7.0.0",
     "atom-package-deps": "^4.0.1",
     "htmlhint": "0.9.13",
     "strip-json-comments": "^2.0.1",