Align with skeleton: update eslint-plugin-html and gulp-stylelint

Author: web-padawan

package.json

@@ -25,7 +25,7 @@
     "bower": "latest",
     "eslint": "^4.0.0",
     "eslint-config-vaadin": "latest",
-    "eslint-plugin-html": "^3.0.0",
+    "eslint-plugin-html": "^4.0.0",
     "gulp": "latest",
     "gulp-clip-empty-files": "^0.1.2",
     "gulp-eslint": "^4.0.0",
@@ -35,7 +35,7 @@
     "gulp-grep-contents": "0.0.1",
     "gulp-html-extract": "^0.3.0",
     "gulp-replace": "^0.6.1",
-    "gulp-stylelint": "^4.0.0",
+    "gulp-stylelint": "^6.0.0",
     "polymer-cli": "^1.2.0",
     "stylelint": "^8.0.0",
     "stylelint-config-vaadin": "latest",