specs-go/config: Use a pointer for Process.ConsoleSize

Fix:

  $ go test ./round_trip_test.go
  --- FAIL: TestConfigRoundTrip (0.00s)
      --- FAIL: TestConfigRoundTrip/config_1 (0.00s)
          round_trip_test.go:32: failed to round-trip:
                  {"ociVersion":"1.0.0","platform":{"os":"linux","arch":"amd64"},"process":{"consoleSize":{"height":0,"width":0},"user":{"uid":1,"gid":1},"args":["sh"],"cwd":"/"},"root":{"path":"rootfs"}}
  FAIL
  FAIL    command-line-arguments  0.003s

By using a pointer for this optional struct property.  Background on
this in [1].

[1]: golang/go#11939

Signed-off-by: W. Trevor King <wking@tremily.us>

Author: wking

specs-go/config.go

@@ -34,7 +34,7 @@ type Process struct {
 	// Terminal creates an interactive terminal for the container.
 	Terminal bool `json:"terminal,omitempty"`
 	// ConsoleSize specifies the size of the console.
-	ConsoleSize Box `json:"consoleSize,omitempty"`
+	ConsoleSize *Box `json:"consoleSize,omitempty"`
 	// User specifies user information for the process.
 	User User `json:"user"`
 	// Args specifies the binary and arguments for the application to execute.