Rename bash command to shell

@iwilltry42 suggested to group all shell support under and single
subcommand -- shell.

cli/commands.go

@@ -354,6 +354,6 @@ func GetKubeConfig(c *cli.Context) error {
 	return nil
 }
 
-func Bash(c *cli.Context) error {
+func Shell(c *cli.Context) error {
 	return bashShell(c.String("name"), c.String("command"))
 }

main.go

@@ -46,9 +46,9 @@ func main() {
 			Action:  run.CheckTools,
 		},
 		{
-			// bash starts a bash shell in the context of a runnign cluster
-			Name:  "bash",
-			Usage: "Start a bash subshell for a cluster",
+			// shell starts a shell in the context of a running cluster
+			Name:  "shell",
+			Usage: "Start a subshell for a cluster",
 			Flags: []cli.Flag{
 				cli.StringFlag{
 					Name:  "name, n",
@@ -60,7 +60,7 @@ func main() {
 					Usage: "Run a shell command in the context of the cluster",
 				},
 			},
-			Action: run.Bash,
+			Action: run.Shell,
 		},
 		{
 			// create creates a new k3s cluster in docker containers