Update dependency mocha to v7.2.0

Author: renovate-bot

package.json

@@ -30,7 +30,7 @@
     "eslint": "6.8.0",
     "eslint-config-theme-next": "1.1.4",
     "hexo": "4.2.0",
-    "mocha": "7.1.1",
+    "mocha": "7.2.0",
     "nyc": "15.0.1"
   }
 }