Bump to v4.0.0.

toUpper.js

@@ -0,0 +1,26 @@
+import toString from './toString';
+
+/**
+ * Converts `string`, as a whole, to upper case.
+ *
+ * @static
+ * @memberOf _
+ * @category String
+ * @param {string} [string=''] The string to convert.
+ * @returns {string} Returns the upper cased string.
+ * @example
+ *
+ * _.toUpper('--foo-bar');
+ * // => '--FOO-BAR'
+ *
+ * _.toUpper('fooBar');
+ * // => 'FOOBAR'
+ *
+ * _.toUpper('__foo_bar__');
+ * // => '__FOO_BAR__'
+ */
+function toUpper(value) {
+  return toString(value).toUpperCase();
+}
+
+export default toUpper;