fix: make the email input required for joining waitlist

Author: skeptrunedev

website/src/pages/index.astro

@@ -33,6 +33,7 @@ invariant(i18n, "No homepage content found");
           type="email"
           placeholder={i18n.waitlist.inputPlaceholder}
           class="border border-btcgray-300 p-3 rounded mb-1 focus:ring-2 focus:ring-brand-500 outline-none"
+          required
         />
         <p class="text-sm text-btcgray-600">
           &rarr; <span id="subscriber-count-value">4</span>