Add alt attribute to img tag in menu (#64)

Author: jbampton

content/theme/templates/menu.html

@@ -1,7 +1,7 @@
 <!-- nav bar -->
 <nav class="navbar navbar-expand-lg navbar-dark bg-info" aria-label="Fifth navbar example">
   <div class="container-fluid">
-    <a class="navbar-brand" href="/"><img src="https://apache.org/img/asf_logo.png" style="height: 42px;"/>
+    <a class="navbar-brand" href="/"><img src="https://apache.org/img/asf_logo.png" alt="The Apache Software Foundation" style="height: 42px;"/>
       <span style="position: relative; top: 5px; margin-left: 16px;">Tooling Initiative</span></a>
     <button class="navbar-toggler" type="button" data-bs-toggle="collapse" data-bs-target="#navbarADP" aria-controls="navbarADP" aria-expanded="false" aria-label="Toggle navigation">
       <span class="navbar-toggler-icon"></span>