Bump esp-web-tools@3.3.0 (#20)

index.html

@@ -71,7 +71,7 @@
         // In development we import locally.
         window.location.hostname === "localhost"
           ? "/dist/web/install-button.js"
-          : "https://unpkg.com/esp-web-tools@3.1.0/dist/web/install-button.js?module"
+          : "https://unpkg.com/esp-web-tools@3.3.0/dist/web/install-button.js?module"
       );
     </script>
   </head>