Update github.com/containerd/containerd

$ go get -u github.ccom/containerd/containerd
$ make vendor

... to silence warnings about https://github.com/advisories/GHSA-crp2-qrr5-8pq7 ,
in code we don't use.

Signed-off-by: Miloslav Trmač <mitr@redhat.com>

vendor/google.golang.org/grpc/internal/envconfig/envconfig.go

@@ -22,20 +22,14 @@ package envconfig
 import (
 	"os"
 	"strings"
-
-	xdsenv "google.golang.org/grpc/internal/xds/env"
 )
 
 const (
 	prefix          = "GRPC_GO_"
-	retryStr        = prefix + "RETRY"
 	txtErrIgnoreStr = prefix + "IGNORE_TXT_ERRORS"
 )
 
 var (
-	// Retry is enabled unless explicitly disabled via "GRPC_GO_RETRY=off" or
-	// if XDS retry support is explicitly disabled.
-	Retry = !strings.EqualFold(os.Getenv(retryStr), "off") && xdsenv.RetrySupport
 	// TXTErrIgnore is set if TXT errors should be ignored ("GRPC_GO_IGNORE_TXT_ERRORS" is not "false").
 	TXTErrIgnore = !strings.EqualFold(os.Getenv(txtErrIgnoreStr), "false")
 )