Bump axios and pm2

Removes [axios](https://github.com/axios/axios). It's no longer used after updating ancestor dependency [pm2](https://github.com/Unitech/pm2). These dependencies need to be updated together.


Removes `axios`

Updates `pm2` from 5.2.0 to 5.3.1
- [Release notes](https://github.com/Unitech/pm2/releases)
- [Changelog](https://github.com/Unitech/pm2/blob/master/CHANGELOG.md)
- [Commits](Unitech/pm2@5.2.0...v5.3.1)

---
updated-dependencies:
- dependency-name: axios
  dependency-type: indirect
- dependency-name: pm2
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

package.json

@@ -29,7 +29,7 @@
         "discord.js": "^12.5.3",
         "log4js": "^6.7.0",
         "mongodb": "^3.7.3",
-        "pm2": "^5.2.0",
+        "pm2": "^5.3.1",
         "qrcode": "^1.5.1"
     },
     "devDependencies": {