fix(CustomInput): fix Invalid propType. (#994)

Closes #993

Author: jasco

docs/lib/Components/FormPage.js

@@ -79,7 +79,7 @@ export default class FormPage extends React.Component {
   invalid: PropTypes.bool, // applied the is-valid class when true, does nothing when false
   bsSize: PropTypes.string,
   cssModule: PropTypes.object,
-  children: PropTypes.oneOfType(PropTypes.node, PropTypes.array, PropTypes.func) // for type="select"
+  children: PropTypes.oneOfType([PropTypes.node, PropTypes.array, PropTypes.func]) // for type="select"
 };`}
           </PrismCode>
         </pre>

src/CustomInput.js

@@ -13,7 +13,7 @@ const propTypes = {
   invalid: PropTypes.bool,
   bsSize: PropTypes.string,
   cssModule: PropTypes.object,
-  children: PropTypes.oneOfType(PropTypes.node, PropTypes.array, PropTypes.func)
+  children: PropTypes.oneOfType([PropTypes.node, PropTypes.array, PropTypes.func])
 };
 
 function CustomInput(props) {