Add String function to oci.Runtime interface

Signed-off-by: Evan Lezar <elezar@nvidia.com>

internal/oci/runtime.go

@@ -16,10 +16,11 @@
 
 package oci
 
-//go:generate moq -stub -out runtime_mock.go . Runtime
-
 // Runtime is an interface for a runtime shim. The Exec method accepts a list
 // of command line arguments, and returns an error / nil.
+//
+//go:generate moq -rm -stub -out runtime_mock.go . Runtime
 type Runtime interface {
 	Exec([]string) error
+	String() string
 }