Bump deps

vendor/github.com/google/go-github/github/messages.go

@@ -33,6 +33,8 @@ const (
 	signatureHeader = "X-Hub-Signature"
 	// eventTypeHeader is the GitHub header key used to pass the event type.
 	eventTypeHeader = "X-Github-Event"
+	// deliveryIDHeader is the GitHub header key used to pass the unique ID for the webhook event.
+	deliveryIDHeader = "X-Github-Delivery"
 )
 
 var (
@@ -54,6 +56,7 @@ var (
 		"membership":                            "MembershipEvent",
 		"milestone":                             "MilestoneEvent",
 		"organization":                          "OrganizationEvent",
+		"org_block":                             "OrgBlockEvent",
 		"page_build":                            "PageBuildEvent",
 		"ping":                                  "PingEvent",
 		"project":                               "ProjectEvent",
@@ -159,10 +162,19 @@ func validateSignature(signature string, payload, secretKey []byte) error {
 }
 
 // WebHookType returns the event type of webhook request r.
+//
+// GitHub API docs: https://developer.github.com/v3/repos/hooks/#webhook-headers
 func WebHookType(r *http.Request) string {
 	return r.Header.Get(eventTypeHeader)
 }
 
+// DeliveryID returns the unique delivery ID of webhook request r.
+//
+// GitHub API docs: https://developer.github.com/v3/repos/hooks/#webhook-headers
+func DeliveryID(r *http.Request) string {
+	return r.Header.Get(deliveryIDHeader)
+}
+
 // ParseWebHook parses the event payload. For recognized event types, a
 // value of the corresponding struct type will be returned (as returned
 // by Event.ParsePayload()). An error will be returned for unrecognized event