Fix react-scripts to work with alphas after 16.0.0

The current logic just checks if the version is an alpha with a major version of 16 to account for weirdness with the 16 RC releases, but now we have alphas for newer minor releases that don't have weirdness

fixtures/dom/package.json

@@ -13,7 +13,7 @@
     "query-string": "^4.2.3",
     "react": "^15.4.1",
     "react-dom": "^15.4.1",
-    "semver": "^5.3.0"
+    "semver": "^5.5.0"
   },
   "scripts": {
     "start": "react-scripts start",

fixtures/dom/src/react-loader.js

@@ -1,3 +1,5 @@
+import semver from 'semver'
+
 /**
  * Take a version from the window query string and load a specific
  * version of React.
@@ -46,10 +48,13 @@ export default function loadReact() {
   let query = parseQuery(window.location.search);
   let version = query.version || 'local';
 
+
   if (version !== 'local') {
+    const {major, minor, prerelease} = semver(version);
+    const [preReleaseStage, preReleaseVersion] = prerelease;
     // The file structure was updated in 16. This wasn't the case for alphas.
     // Load the old module location for anything less than 16 RC
-    if (parseInt(version, 10) >= 16 && version.indexOf('alpha') < 0) {
+    if (major >= 16 && !(minor === 0 && preReleaseStage === 'alpha')) {
       REACT_PATH =
         'https://unpkg.com/react@' + version + '/umd/react.development.js';
       DOM_PATH =

fixtures/dom/yarn.lock

@@ -5890,6 +5890,10 @@ semver@^5.0.3:
   version "5.4.1"
   resolved "https://registry.yarnpkg.com/semver/-/semver-5.4.1.tgz#e059c09d8571f0540823733433505d3a2f00b18e"
 
+semver@^5.5.0:
+  version "5.5.0"
+  resolved "https://registry.yarnpkg.com/semver/-/semver-5.5.0.tgz#dc4bbc7a6ca9d916dee5d43516f0092b58f7b8ab"
+
 send@0.14.1:
   version "0.14.1"
   resolved "https://registry.yarnpkg.com/send/-/send-0.14.1.tgz#a954984325392f51532a7760760e459598c89f7a"