Update README.md

Parse Github pull request labels from pull request payload.

README.md

@@ -1,6 +1,6 @@
 Library webhooks
 ================
-<img align="right" src="https://raw.githubusercontent.com/go-playground/webhooks/v3/logo.png">![Project status](https://img.shields.io/badge/version-3.10.0-green.svg)
+<img align="right" src="https://raw.githubusercontent.com/go-playground/webhooks/v3/logo.png">![Project status](https://img.shields.io/badge/version-3.11.0-green.svg)
 [![Build Status](https://travis-ci.org/go-playground/webhooks.svg?branch=v3)](https://travis-ci.org/go-playground/webhooks)
 [![Coverage Status](https://coveralls.io/repos/go-playground/webhooks/badge.svg?branch=v3&service=github)](https://coveralls.io/github/go-playground/webhooks?branch=v3)
 [![Go Report Card](https://goreportcard.com/badge/go-playground/webhooks)](https://goreportcard.com/report/go-playground/webhooks)

github/payload.go

@@ -2791,6 +2791,13 @@ type PullRequestPayload struct {
 			Type              string `json:"type"`
 			SiteAdmin         bool   `json:"site_admin"`
 		} `json:"requested_reviewers,omitempty"`
+		Labels []struct {
+			ID      int64  `json:"id"`
+			URL     string `json:"url"`
+			Name    string `json:"name"`
+			Color   string `json:"color"`
+			Default bool   `json:"default"`
+		} `json:"labels"`
 		Head struct {
 			Label string `json:"label"`
 			Ref   string `json:"ref"`