chore(demo): change github branch to master

Author: javier-godoy

src/test/java/com/flowingcode/vaadin/addons/imagecrop/ImageCropDemoView.java

@@ -29,7 +29,7 @@
 @SuppressWarnings("serial")
 @ParentLayout(DemoLayout.class)
 @Route("image-crop")
-@GithubBranch("initial-implementation")
+@GithubBranch("master")
 @GithubLink("https://github.com/FlowingCode/ImageCrop")
 public class ImageCropDemoView extends TabbedDemo {