Add shadow to anniversary banner button

Author: tobihagemann

layouts/partials/anniversary-banner.html

@@ -1,6 +1,6 @@
 <section class="absolute inset-x-0 top-16 z-40" role="region" aria-label="{{ i18n "anniversary_banner_aria_label" . }}">
   <div class="container py-1.5 md:py-2">
-    <a href="https://www.reddit.com/r/Cryptomator/comments/1rjt0yh/join_our_10year_anniversary_ama_with_the/" class="btn btn-primary flex w-full items-center gap-1 px-2 text-xs md:justify-center md:gap-3 md:px-4 md:text-sm" target="_blank" rel="noopener" data-umami-event="anniversary-banner-reddit">
+    <a href="https://www.reddit.com/r/Cryptomator/comments/1rjt0yh/join_our_10year_anniversary_ama_with_the/" class="btn btn-primary flex shadow-sm hover:shadow-md w-full items-center gap-1 px-2 text-xs md:justify-center md:gap-3 md:px-4 md:text-sm" target="_blank" rel="noopener" data-umami-event="anniversary-banner-reddit">
       <img src="/img/logo-anniversary.svg" class="h-9 shrink-0 mr-2 md:h-7 md:mr-0" alt="10 years anniversary logo" loading="lazy">
       <span class="flex flex-wrap items-center gap-x-1 gap-y-0.5 md:justify-center">
         <span class="font-semibold">{{ i18n "anniversary_banner_lead" . }}</span>