react-dom-server dependency build is broken

[nylen]

While reviewing #1624 I noticed that
https://unpkg.com/react-dom@next/umd/react-dom-server.development.js is currently a bad build. This is breaking master for me 😞

It redirects to https://unpkg.com/react-dom@16.0.0-alpha.13/umd/react-dom-server.development.js which ends like this:

/**
* For browsers that do not provide the `textInput` event, extract the
* appropriate string to use for SyntheticInputEvent.
*
* @param {string} topLevelType Record from `BrowserEventConstants`.
* @param {object} nativeEvent Native browser event.
* @return {?string} The fallback string for this `beforeInput` event.
*/
function getFallbackBeforeInputChars(topLevelType, nativeEvent) {
 // If we are currently composing (IME) and using a fallback to do so,
 // try to extract the composed characters from the fallback object.
 // If composition event is available, we extract a string only at
 // compositionevent, otherwise extract it at fallback events.
 if (currentComposition) {
   if (topLevelType === 'topCompositionEnd' || !canUseCompositionEve

The alpha.12 version looks fine; here is what I did as a temp. fix

sudo -u www-data wget https://unpkg.com/react-dom@16.0.0-alpha.12/umd/react-dom-server.development.js -O vendor/react-dom-server.e84b9fa6.js

If this is not resolved soon, we can depend on this version directly instead of @next.

[nylen]

This seems to have fixed itself.