Update GenerateAppImage.java

Author: fvarrui

src/main/java/io/github/fvarrui/javapackager/packagers/GenerateAppImage.java

@@ -13,7 +13,7 @@
 public class GenerateAppImage extends ArtifactGenerator<LinuxPackager> {
 
 	private static final int IMAGETOOL_VERSION = 13;
-	private static final String IMAGETOOL_URL = "https://github.com/AppImage/AppImageKit/releases/download/%d/appimagetool-%s.AppImage".formatted(IMAGETOOL_VERSION, SystemUtils.OS_ARCH);
+	private static final String IMAGETOOL_URL = "https://github.com/AppImage/AppImageKit/releases/download/" + IMAGETOOL_VERSION + "/appimagetool-" + SystemUtils.OS_ARCH + ".AppImage";
 
 	public GenerateAppImage() {
 		super("AppImage");