fix(@angular-devkit/build-angular): update link to update.angular.io

This link is rarely seen by developers but when they do see it, they should get the real one.

(cherry picked from commit 17792c4)

packages/angular_devkit/build_angular/src/utils/version.ts

@@ -73,7 +73,7 @@ export function assertCompatibleAngularVersion(projectRoot: string, logger: logg
         but Angular version ${angularVersion} was found instead.
 
         Please visit the link below to find instructions on how to update Angular.
-        https://angular-update-guide.firebaseapp.com/
+        https://update.angular.io/
       ` + '\n',
     );