cli: use auto proto for ws url

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

.changeset/pink-mirrors-cry.md

@@ -0,0 +1,5 @@
+---
+'@backstage/cli': patch
+---
+
+Switched the `WebpackDevServer` configuration to use client-side detection of the WebSocket protocol.

packages/cli/src/lib/bundler/server.ts

@@ -67,6 +67,9 @@ export async function serveBundle(options: ServeOptions) {
       proxy: pkg.proxy,
       // When the dev server is behind a proxy, the host and public hostname differ
       allowedHosts: [url.hostname],
+      client: {
+        webSocketURL: 'auto://0.0.0.0:0/ws',
+      },
     } as any,
   );