update badge to v1.1 (#140)

changed badge from Beta to v1.1

static/header.html

@@ -11,6 +11,6 @@
     <h2 style="margin: 0;">NatureLM-audio<span style="
         font-size: 0.55em; color: #28a745; background: #e6f4ea;
         padding: 2px 6px; border-radius: 4px; margin-left: 8px;
-        display: inline-block; vertical-align: top;"
-    >BETA</span></h2>
+        display: inline-block; vertical-align: middle;"
+    >v1.1</span></h2>
 </div>