redfish/updateservice: Add struct field MultipartHTTPPushURI (#166)

A service may support the MultipartHttpPushUri property within the
UpdateService resource.
A client can perform an HTTP or HTTPS POST request on the URI specified by this
property to initiate a push-based update.

ref: https://www.dmtf.org/sites/default/files/standards/documents/DSP0266_1.15.0.pdf

redfish/updateservice.go

@@ -26,6 +26,8 @@ type UpdateService struct {
 	SoftwareInventory string
 	// HTTPPushURI endpoint is used to push (POST) firmware updates
 	HTTPPushURI string `json:"HttpPushUri"`
+	// MultipartHTTPPushURI endpoint is used to perform a multipart push (POST) updates
+	MultipartHTTPPushURI string `json:"MultiPartHttpPushUri"`
 	// ServiceEnabled indicates whether this service isenabled.
 	ServiceEnabled bool
 	// Status describes the status and health of a resource and its children.