Add a disclaimer message for all `docker compose` commands

Signed-off-by: Guillaume Tardif <[email protected]>

cli/cmd/compose/compose.go

@@ -17,6 +17,8 @@
 package compose
 
 import (
+	"fmt"
+
 	"github.com/compose-spec/compose-go/cli"
 	"github.com/compose-spec/compose-go/types"
 	"github.com/spf13/cobra"
@@ -72,6 +74,10 @@ func Command(contextType string) *cobra.Command {
 	command := &cobra.Command{
 		Short: "Docker Compose",
 		Use:   "compose",
+		PersistentPreRunE: func(cmd *cobra.Command, args []string) error {
+			fmt.Println("The new 'docker compose' command is currently experimental. To provide feedback or request new features please open issues at https://github.com/docker/compose-cli")
+			return nil
+		},
 	}
 
 	command.AddCommand(