package.json edited include sitemap.txt (#141)

* package.json edited

* edit version

* Update package.json

Co-authored-by: yoshinorin <yoshinorin.net@outlook.com>

Author: uiolee

package.json

@@ -1,6 +1,6 @@
 {
   "name": "hexo-generator-sitemap",
-  "version": "3.0.0",
+  "version": "3.0.1",
   "description": "Sitemap generator plugin for Hexo",
   "main": "index",
   "scripts": {
@@ -14,7 +14,8 @@
   "files": [
     "lib",
     "index.js",
-    "sitemap.xml"
+    "sitemap.xml",
+    "sitemap.txt"
   ],
   "repository": "hexojs/hexo-generator-sitemap",
   "keywords": [