migrate to chai@5

Author: uiolee

.mocharc.yml

@@ -1 +1,3 @@
 color: true
+require:
+  - "chai/register-should.js"

test/index.js

@@ -1,6 +1,5 @@
 'use strict';
 
-require('chai').should();
 const { encodeURL, escapeHTML, url_for } = require('hexo-util');
 const Hexo = require('hexo');
 const { join } = require('path').posix;