Update c/image with https://github.com/containers/image/pull/1944

... to update github.com/opencontainers/image-spec to v1.1.0-rc3.

Signed-off-by: Miloslav Trmač <mitr@redhat.com>

vendor/github.com/go-openapi/spec/info.go

@@ -16,6 +16,7 @@ package spec
 
 import (
 	"encoding/json"
+	"strconv"
 	"strings"
 
 	"github.com/go-openapi/jsonpointer"
@@ -40,6 +41,24 @@ func (e Extensions) GetString(key string) (string, bool) {
 	return "", false
 }
 
+// GetInt gets a int value from the extensions
+func (e Extensions) GetInt(key string) (int, bool) {
+	realKey := strings.ToLower(key)
+
+	if v, ok := e.GetString(realKey); ok {
+		if r, err := strconv.Atoi(v); err == nil {
+			return r, true
+		}
+	}
+
+	if v, ok := e[realKey]; ok {
+		if r, rOk := v.(float64); rOk {
+			return int(r), true
+		}
+	}
+	return -1, false
+}
+
 // GetBool gets a string value from the extensions
 func (e Extensions) GetBool(key string) (bool, bool) {
 	if v, ok := e[strings.ToLower(key)]; ok {