fix: avatar resolution (#383)

This will bring the "Best Practices" score from 92 to 100. #268 

<img width="753" alt="Screenshot 2023-07-19 at 21 01 16"
src="https://github.com/denoland/saaskit/assets/8139585/aee1d398-3409-46da-a093-154af17ceb2a">

components/UserPostedAt.tsx

@@ -8,8 +8,9 @@ export default function UserPostedAt(
   return (
     <p class="text-gray-500">
       <img
-        // Resize the avatar image to be 24x24 px
-        src={props.user.avatarUrl + "&s=24"}
+        // Resize the avatar image to be 36x36 px
+        // Although display size is 24x24, lighthouse complains about low resolution if the image is 24x24
+        src={props.user.avatarUrl + "&s=36"}
         alt={props.user.login}
         crossOrigin="anonymous"
         class="h-6 w-auto rounded-full inline-block mr-2"