Updates oci image config to support upstream ArgsEscaped

ArgsEscaped has now been merged into upstream OCI image spec.
This change removes the workaround we were doing in containerd
to deserialize the extra json outside of the spec and instead
just uses the formal spec types.

Signed-off-by: Justin Terry <jlterry@amazon.com>

vendor/github.com/opencontainers/image-spec/specs-go/v1/config.go

@@ -48,6 +48,15 @@ type ImageConfig struct {
 
 	// StopSignal contains the system call signal that will be sent to the container to exit.
 	StopSignal string `json:"StopSignal,omitempty"`
+
+	// ArgsEscaped `[Deprecated]` - This field is present only for legacy
+	// compatibility with Docker and should not be used by new image builders.
+	// It is used by Docker for Windows images to indicate that the `Entrypoint`
+	// or `Cmd` or both, contains only a single element array, that is a
+	// pre-escaped, and combined into a single string `CommandLine`. If `true`
+	// the value in `Entrypoint` or `Cmd` should be used as-is to avoid double
+	// escaping.
+	ArgsEscaped bool `json:"ArgsEscaped,omitempty"`
 }
 
 // RootFS describes a layer content addresses