feat: support build tag to reduce binary size w/o k8s (#4323)

zrpc/resolver/internal/register.go

@@ -0,0 +1,8 @@
+//go:build no_k8s
+
+package internal
+
+// RegisterResolver registers the direct, etcd and discov schemes to the resolver.
+func RegisterResolver() {
+	register()
+}