Dev dependencies (#897)

* Upgrade eslint

* Upgrade rollup

* Upgrade mocha

* Upgrade gulp

* Upgrade more gulp

* Upgrade frontend stuff

package.json

@@ -41,13 +41,13 @@
     "del": "^3.0.0",
     "eslint": "^4.11.0",
     "eslint-config-airbnb-base": "^12.1.0",
-    "eslint-plugin-html": "^3.2.2",
+    "eslint-plugin-html": "^4.0.0",
     "eslint-plugin-import": "^2.8.0",
     "eslint-plugin-react": "^7.0.0",
     "gulp": "^3.9.1",
     "gulp-babel": "^7.0.0",
     "gulp-batch-replace": "^0.0.0",
-    "gulp-file": "^0.3.0",
+    "gulp-file": "^0.4.0",
     "gulp-filter": "^5.0.1",
     "gulp-foreach": "^0.1.0",
     "gulp-gzip": "^1.4.0",
@@ -67,16 +67,16 @@
     "gulp-zopfli": "^1.0.0",
     "html-minifier": "^3.5.6",
     "merge-stream": "^1.0.1",
-    "mocha": "^4.0.1",
+    "mocha": "^5.0.0",
     "parse5": "^3.0.3",
     "polymer-analyzer": "^2.3.0",
     "polymer-build": "^2.1.0",
     "polymer-bundler": "^3.1.0",
     "polymer-cli": "^1.5.6",
-    "pump": "^1.0.2",
+    "pump": "^3.0.0",
-    "reify": "^0.12.3",
+    "reify": "^0.14.1",
-    "require-dir": "^0.3.2",
+    "require-dir": "^1.0.0",
-    "rollup": "^0.51.3",
+    "rollup": "^0.56.0",
     "rollup-plugin-babel": "^3.0.2",
     "rollup-plugin-commonjs": "^8.2.6",
     "rollup-plugin-node-resolve": "^3.0.0",