chore(accessibility): add H1 header

Fixes #34

build/templates/index.html

@@ -31,7 +31,7 @@
 
     <div class="flex flex-col min-h-screen">
         <header class="mt-24 px-4 text-center space-y-5">
-          <p class="max-w-lg mx-auto"><img width="512px" height="190px" class="mx-auto" src="images/fabric-notes-header.svg" alt="Fabric Notes" /></p>
+          <h1 class="max-w-lg mx-auto"><img width="512px" height="190px" class="mx-auto" src="images/fabric-notes-header.svg" alt="Fabric Notes" /></h1>
           <p class="text-xl mx-4">Simple drawings illustrating the main concepts of <span class="font-bold text-teal-700">Microsoft Fabric</span> to empower anyone to build stuff on Fabric.</p>
           <div role="heading" aria-level="2" aria-label="Note for people using a screen reader: This website is a collection of drawings. For each drawing, we are only giving a one-sentence phrase describing it, but it's not sufficient. We welcome contributions to make these fabric notes accessible."></div>
           <p class="text-gray-700">Inspired by <a class="text-blue-600 underline" href="https://azurecosmosdb.github.io/CosmicNotes/">🌍 Cosmic Notes</a></p>