added excel sheet link

lib/widgets/linkButton.dart

@@ -0,0 +1,25 @@
+import "package:flutter/material.dart";
+import "package:url_launcher/url_launcher.dart";
+
+class LinkButton extends StatelessWidget {
+  final Uri link;
+  final String iconImage;
+  final double height;
+  const LinkButton(
+      {Key? key, required this.link, required this.iconImage, this.height = 30})
+      : super(key: key);
+
+  @override
+  Widget build(BuildContext context) {
+    return Padding(
+      padding: const EdgeInsets.all(8.0),
+      child: InkWell(
+          child: Image(image: AssetImage(iconImage), height: height),
+          onTap: () async {
+            if (await canLaunchUrl(link)) {
+              launchUrl(link);
+            }
+          }),
+    );
+  }
+}