implement basic exec [ci skip]

engine/linter/linter.go

@@ -139,6 +139,8 @@ func checkVolumes(pipeline *resource.Pipeline, trusted bool) error {
 			}
 		}
 		switch volume.Name {
+		case "":
+			return fmt.Errorf("linter: missing volume name")
 		case "workspace", "_workspace", "_docker_socket":
 			return fmt.Errorf("linter: invalid volume name: %s", volume.Name)
 		}