vendor: Update virtcontainers vendoring

Update virtcontainers version vendored into the runtime, addding the
new nsenter package so that our shims are now entering both network
and PID namespaces.
It also includes new Kata Containers agent protocol updates related
to networking and devices. Those are needed for latest network
support, block device passthrough, and devicemapper rootfs.
It also fixes some linter errors and improve the docs.
It adds the support for CPU hotplug.

Shortlog:

12f35ce qemu: enable CPU hotplug
925a70c pod: hot add/remove vCPUs before starting containers
4a84438 qemu: Add support for CPU hot add/remove
c17c48d vendor: Constraint containerd vendoring
c9996f3 filesystem: set correct access mode for pod dir tree
4f9cb18 kata_agent: Add nouuid option for xfs filesystem
085848b kata_agent: Provide hotplugged device the right rootfs path
9ef18a6 kata_agent: Update host and guest paths for Kata
2c88b8e kata_agent: Wait for rootfs if it is a hotplugged device
15a4d17 kata_agent: Support block device passthrough
fd5b27f vendor: Update Kata agent protocol
0519e89 check: lint: ineffassign in qemu.go
ae661c5 network: Fix lint errors
5c73774 shim: Start shims inside PID namespace
6d7f6e5 shim: Add ability to enter any set of namespaces
f318b77 shim: Add the ability to spawn the shim in new namespaces
fefb087 pkg: nsenter: Introduce a generic nsenter package
43c05c2 utils: setup: Add some more prereq checks to the setup script.
1a25bad docs: developers: Add some developer docs
43c9ed3 kata-agent: add initial test for kata-agent networking
082ec3f kata-agent: add network gRPC support
4b30262 setup: #!/bin/bash in the wrong place
8b7fddf vendor: re-vendor kata-containers agent

Fixes #1043

Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>

Gopkg.toml

@@ -24,7 +24,7 @@
 
 [[constraint]]
   name = "github.com/containers/virtcontainers"
-  revision = "494b46c5bfa0c305fa3e2ad9d15ca12af2c148a5"
+  revision = "c88890875e8d4ce31a0664d6a7e7ca637aae9045"
 
 [prune]
   non-go = true