sandbox: support vsock connection to task api

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

vendor/github.com/mdlayher/vsock/README.md

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+# vsock [![Test Status](https://github.com/mdlayher/vsock/workflows/Linux%20Test/badge.svg)](https://github.com/mdlayher/vsock/actions) [![Go Reference](https://pkg.go.dev/badge/github.com/mdlayher/vsock.svg)](https://pkg.go.dev/github.com/mdlayher/vsock)  [![Go Report Card](https://goreportcard.com/badge/github.com/mdlayher/vsock)](https://goreportcard.com/report/github.com/mdlayher/vsock)
+
+Package `vsock` provides access to Linux VM sockets (`AF_VSOCK`) for
+communication between a hypervisor and its virtual machines.  MIT Licensed.
+
+For more information about VM sockets, see my blog about
+[Linux VM sockets in Go](https://mdlayher.com/blog/linux-vm-sockets-in-go/) or
+the [QEMU wiki page on virtio-vsock](http://wiki.qemu-project.org/Features/VirtioVsock).
+
+## Stability
+
+See the [CHANGELOG](./CHANGELOG.md) file for a description of changes between
+releases.
+
+This package has a stable v1 API and any future breaking changes will prompt
+the release of a new major version. Features and bug fixes will continue to
+occur in the v1.x.x series.
+
+This package only supports the two most recent major versions of Go, mirroring
+Go's own release policy. Older versions of Go may lack critical features and bug
+fixes which are necessary for this package to function correctly.