Convert CLI to urfave v2

Followed the Migration Guide at https://cli.urfave.org/migrate-v1-to-v2/
The major changes not pointed out in the migration guide are:
- context.Args() no longer produces a []slice, so context.Args().Slice()
  in substitued
- All cli.Global***** are deprecated (the migration guide is somewhat
  unclear on this)

Signed-off-by: Derek Nola <derek.nola@suse.com>

Vendor in urfave cli/v2

Signed-off-by: Derek Nola <derek.nola@suse.com>

Fix NewStringSlice calls

Signed-off-by: Derek Nola <derek.nola@suse.com>

cmd/ctr/commands/run/run.go

@@ -26,7 +26,7 @@ import (
 	"github.com/containerd/console"
 	gocni "github.com/containerd/go-cni"
 	specs "github.com/opencontainers/runtime-spec/specs-go"
-	"github.com/urfave/cli"
+	"github.com/urfave/cli/v2"
 
 	containerd "github.com/containerd/containerd/v2/client"
 	"github.com/containerd/containerd/v2/cmd/ctr/commands"
@@ -89,41 +89,41 @@ func parseMountFlag(m string) (specs.Mount, error) {
 }
 
 // Command runs a container
-var Command = cli.Command{
-	Name:           "run",
-	Usage:          "Run a container",
-	ArgsUsage:      "[flags] Image|RootFS ID [COMMAND] [ARG...]",
-	SkipArgReorder: true,
+var Command = &cli.Command{
+	Name:      "run",
+	Usage:     "Run a container",
+	ArgsUsage: "[flags] Image|RootFS ID [COMMAND] [ARG...]",
 	Flags: append([]cli.Flag{
-		cli.BoolFlag{
+		&cli.BoolFlag{
 			Name:  "rm",
 			Usage: "Remove the container after running, cannot be used with --detach",
 		},
-		cli.BoolFlag{
+		&cli.BoolFlag{
 			Name:  "null-io",
 			Usage: "Send all IO to /dev/null",
 		},
-		cli.StringFlag{
+		&cli.StringFlag{
 			Name:  "log-uri",
 			Usage: "Log uri",
 		},
-		cli.BoolFlag{
-			Name:  "detach,d",
-			Usage: "Detach from the task after it has started execution, cannot be used with --rm",
+		&cli.BoolFlag{
+			Name:    "detach",
+			Aliases: []string{"d"},
+			Usage:   "Detach from the task after it has started execution, cannot be used with --rm",
 		},
-		cli.StringFlag{
+		&cli.StringFlag{
 			Name:  "fifo-dir",
 			Usage: "Directory used for storing IO FIFOs",
 		},
-		cli.StringFlag{
+		&cli.StringFlag{
 			Name:  "cgroup",
 			Usage: "Cgroup path (To disable use of cgroup, set to \"\" explicitly)",
 		},
-		cli.StringFlag{
+		&cli.StringFlag{
 			Name:  "platform",
 			Usage: "Run image for specific platform",
 		},
-		cli.BoolFlag{
+		&cli.BoolFlag{
 			Name:  "cni",
 			Usage: "Enable cni networking for the container",
 		},
@@ -259,7 +259,7 @@ var Command = cli.Command{
 			return err
 		}
 		if code != 0 {
-			return cli.NewExitError("", int(code))
+			return cli.Exit("", int(code))
 		}
 		return nil
 	},