sandbox: support vsock connection to task api

Signed-off-by: Abel Feng <fshb1988@gmail.com>

vendor/github.com/mdlayher/socket/netns_others.go

@@ -0,0 +1,14 @@
+//go:build !linux
+// +build !linux
+
+package socket
+
+import (
+	"fmt"
+	"runtime"
+)
+
+// withNetNS returns an error on non-Linux systems.
+func withNetNS(_ int, _ func() (*Conn, error)) (*Conn, error) {
+	return nil, fmt.Errorf("socket: Linux network namespace support is not available on %s", runtime.GOOS)
+}