docs: add sponsor link (#5597)

docs/src/pages/index.tsx

@@ -32,6 +32,15 @@ function HomepageHeader() {
           >
             Demo portal
           </Link>
+
+          <a
+            href="https://github.com/sponsors/immich-app"
+            target="_blank"
+            rel="noreferrer"
+            className="flex place-items-center place-content-center py-3 px-8 border bg-immich-sponsor rounded-full no-underline hover:no-underline text-white dark:text-immich-dark-bg dark:bg-immich-sponsor hover:text-white font-bold uppercase"
+          >
+            Sponsor
+          </a>
         </div>
 
         <img src="/img/immich-screenshots.png" alt="screenshots" width={'85%'} />

docs/tailwind.config.js

@@ -20,6 +20,8 @@ module.exports = {
         'immich-dark-bg': 'black',
         'immich-dark-fg': '#e5e7eb',
         'immich-dark-gray': '#212121',
+
+        'immich-sponsor': '#db61a2',
       },
       fontFamily: {
         'immich-title': ['Snowburst One', 'cursive'],