App.go Run parallel control issue

[goxiaoy]

What happened:

registrar may not wait all servers ready

https://github.com/go-kratos/kratos/blob/1451b9e0c0e3e1ee88a4595d9f9cfaf24eb8150f/app.go#L103-L106

What you expected to happen:

		eg.Go(func() error {
-                       wg.Done()
+			defer wg.Done()
			return srv.Start(NewContext(a.opts.ctx, a))
		})

How to reproduce it (as minimally and precisely as possible):

Anything else we need to know?:

Environment:

• Kratos version (use kratos -v):
• Go version (use go version):
• OS (e.g: cat /etc/os-release):
• Others: