Merge pull request #569 from kubernetes/greenkeeper-html-minifier-1.3.1

Update html-minifier to version 1.3.1 🚀

Author: bryk

package.json

@@ -48,7 +48,7 @@
     "gulp-useref": "~3.0.4",
     "gulp-util": "~3.0.7",
     "gulp-watch": "~4.3.5",
-    "html-minifier": "~1.2.0",
+    "html-minifier": "~1.3.1",
     "isparta": "~4.0.0",
     "karma": "0.13.22",
     "karma-browserify": "~5.0.3",