Update containerd to v1.2.0.

Signed-off-by: Lantao Liu <lantaol@google.com>

vendor/github.com/Microsoft/hcsshim/internal/schema2/layer.go

@@ -0,0 +1,22 @@
+/*
+ * HCS API
+ *
+ * No description provided (generated by Swagger Codegen https://github.com/swagger-api/swagger-codegen)
+ *
+ * API version: 2.1
+ * Generated by: Swagger Codegen (https://github.com/swagger-api/swagger-codegen.git)
+ */
+
+package hcsschema
+
+type Layer struct {
+
+	Id string `json:"Id,omitempty"`
+
+	Path string `json:"Path,omitempty"`
+
+	PathType string `json:"PathType,omitempty"`
+
+	//  Unspecified defaults to Enabled
+	Cache string `json:"Cache,omitempty"`
+}