fix(deps): update dependency sitemap to v4

Squashed commit of the following:

commit f4dd9cabb21e26fdc21f8413be822ea7c64251f8
Author: Julian Lam <julian@nodebb.org>
Date:   Tue Aug 13 11:33:05 2019 -0400

    fix: resolved breaking changes from sitemap v4 upgrade

commit 9043415ee16dcc27a8dcc2e4479d1bc5e2d1b60e
Merge: e3352b272 72590b346
Author: Julian Lam <julian@nodebb.org>
Date:   Tue Aug 13 11:09:55 2019 -0400

    Merge branch 'master' into renovate/sitemap-4.x

commit e3352b272eb9400bdb00774973181397803765e4
Author: Renovate Bot <bot@renovateapp.com>
Date:   Mon Aug 12 07:59:05 2019 +0000

    fix(deps): update dependency sitemap to v4

install/package.json

@@ -110,7 +110,7 @@
         "semver": "^6.0.0",
         "serve-favicon": "^2.4.5",
         "sharp": "0.23.0",
-        "sitemap": "^3.0.0",
+        "sitemap": "^4.0.0",
         "socket.io": "2.2.0",
         "socket.io-adapter-cluster": "^1.0.1",
         "socket.io-adapter-mongo": "^2.0.1",

src/sitemap.js

@@ -1,7 +1,7 @@
 'use strict';
 
 var async = require('async');
-var sm = require('sitemap');
+const { Sitemap } = require('sitemap');
 var nconf = require('nconf');
 
 var db = require('./database');
@@ -45,7 +45,7 @@ sitemap.getPages = function (callback) {
 		sitemap.maps.pages &&
 		Date.now() < parseInt(sitemap.maps.pages.cacheSetTimestamp, 10) + parseInt(sitemap.maps.pages.cacheResetPeriod, 10)
 	) {
-		return sitemap.maps.pages.toXML(callback);
+		return callback(null, sitemap.maps.pages.toXML());
 	}
 
 	var urls = [{
@@ -70,13 +70,13 @@ sitemap.getPages = function (callback) {
 		if (err) {
 			return callback(err);
 		}
-		sitemap.maps.pages = sm.createSitemap({
+		sitemap.maps.pages = new Sitemap({
 			hostname: nconf.get('url'),
 			cacheTime: 1000 * 60 * 60 * 24,	// Cached for 24 hours
 			urls: data.urls,
 		});
 
-		sitemap.maps.pages.toXML(callback);
+		callback(null, sitemap.maps.pages.toXML());
 	});
 };
 
@@ -85,7 +85,7 @@ sitemap.getCategories = function (callback) {
 		sitemap.maps.categories &&
 		Date.now() < parseInt(sitemap.maps.categories.cacheSetTimestamp, 10) + parseInt(sitemap.maps.categories.cacheResetPeriod, 10)
 	) {
-		return sitemap.maps.categories.toXML(callback);
+		return callback(null, sitemap.maps.categories.toXML());
 	}
 
 	var categoryUrls = [];
@@ -104,13 +104,13 @@ sitemap.getCategories = function (callback) {
 			}
 		});
 
-		sitemap.maps.categories = sm.createSitemap({
+		sitemap.maps.categories = new Sitemap({
 			hostname: nconf.get('url'),
 			cacheTime: 1000 * 60 * 60 * 24,	// Cached for 24 hours
 			urls: categoryUrls,
 		});
 
-		sitemap.maps.categories.toXML(callback);
+		callback(null, sitemap.maps.categories.toXML());
 	});
 };
 
@@ -127,7 +127,7 @@ sitemap.getTopicPage = function (page, callback) {
 		sitemap.maps.topics[page - 1] &&
 		Date.now() < parseInt(sitemap.maps.topics[page - 1].cacheSetTimestamp, 10) + parseInt(sitemap.maps.topics[page - 1].cacheResetPeriod, 10)
 	) {
-		return sitemap.maps.topics[page - 1].toXML(callback);
+		return callback(null, sitemap.maps.topics[page - 1].toXML());
 	}
 
 	var topicUrls = [];
@@ -158,13 +158,13 @@ sitemap.getTopicPage = function (page, callback) {
 			}
 		});
 
-		sitemap.maps.topics[page - 1] = sm.createSitemap({
+		sitemap.maps.topics[page - 1] = new Sitemap({
 			hostname: nconf.get('url'),
 			cacheTime: 1000 * 60 * 60,	// Cached for 1 hour
 			urls: topicUrls,
 		});
 
-		sitemap.maps.topics[page - 1].toXML(callback);
+		callback(null, sitemap.maps.topics[page - 1].toXML());
 	});
 };