Fix using pre-release tags with a tarball url in --scripts-version (f…

…acebook#876)

* Add supports for prelease tags version

* Add comment to regex

* Cut everything after the first -\d

* Make semver version optional, so just package name get parsed correctly

packages/create-react-app/index.js

@@ -153,7 +153,9 @@ function getInstallPackage(version) {
 // Extract package name from tarball url or path.
 function getPackageName(installPackage) {
   if (installPackage.indexOf('.tgz') > -1) {
-    return installPackage.match(/^.+\/(.+)-.+\.tgz$/)[1];
+    // The package name could be with or without semver version, e.g. react-scripts-0.2.0-alpha.1.tgz
+    // However, this function returns package name only wihout semver version.
+    return installPackage.match(/^.+\/(.+?)(?:-\d+.+)?\.tgz$/)[1];
   } else if (installPackage.indexOf('@') > 0) {
     // Do not match @scope/ when stripping off @version or @tag
     return installPackage.charAt(0) + installPackage.substr(1).split('@')[0];