refactor: linting html.js

.eslintrc

@@ -4,5 +4,15 @@
         "react",
         "jsx-a11y",
         "import"
-    ]
+    ],
+    "rules": {
+        "react/jsx-filename-extension": [0],
+        "react/prefer-es6-class": [0],
+        "global-require": [0],
+        "react/prefer-stateless-function": [0],
+        /* to allow importing 'gatsby-helpers' */
+        "import/no-extraneous-dependencies": [0],
+        "import/no-unresolved": [0],
+        "import/extensions": [0]
+    }
 }