Add github link in the about modal

Author: willemarcel

packages/web/src/app/components/header.tsx

@@ -38,6 +38,14 @@ export function Header() {
           Visualize OpenStreetMap features created, modified or deleted every hour
           using change data prepared by OSMCha as a FlatGeobuf. This visualization
           does not use a server.
+          <br/><br/>
+          <a
+            href="https://github.com/developmentseed/osm-gradient"
+            target="_blank"
+            rel="noreferrer noopener"
+          >
+            GitHub
+          </a>
         </small>
       </dialog>
       <button

packages/web/src/index.css

@@ -102,6 +102,10 @@ dialog {
   box-shadow:
     0 2px 6px 0 var(--bg-dark),
     0 6px 6px -2px rgba(120, 120, 120, 0.125);
+  & a {
+    color: var(--base-light);
+    text-decoration: underline;
+  }
 }
 .dialog--header {
   display: flex;