Make using require() a warning

Summary: Per title. Let's be more consistent, especially for plugins where authors may not know which one to use.

Reviewed By: jknoxville

Differential Revision: D16340189

fbshipit-source-id: ffe49e509f744279e32fc9fc3f1d59efc1328d80

src/.eslintrc.js

@@ -0,0 +1,20 @@
+/**
+ * Copyright 2018-present Facebook.
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ * @format
+ */
+
+// Eslint rules cascade. Rules defined here are merged with the rules
+// defined in the parent directory.
+
+// Somewhat ironically, this particular file is not actually transformed by Babel
+// and can't have ES6 imports/exports.
+// eslint-disable-line import/no-commonjs
+module.exports = {
+  plugins: ['import'],
+  rules: {
+    // Import rules from https://www.npmjs.com/package/eslint-plugin-import
+    'import/no-commonjs': 1,
+  },
+};