Unable to connect to MongoDB with TLS

**🐞 Describe the bug**
Using TLS connection with MongoDB, Ackee doesn't start.

**📚 To Reproduce**

1. set `ACKEE_MONGODB=mongodb+srv://ackee:password@db.leafia.net/ackee` or `ACKEE_MONGODB=mongodb://ackee:password@db.leafia.net/ackee?tls=true`
2. start Ackee

**💡 Expected behavior**

Ackee starts successfully.

**⚙️ Environment**
- Installation: Manually
- Ackee version: [e.g. v2.1.0]

**📋 Log**
```
5月 03 12:15:37 ls.leafia.net yarn[186333]: > ackee@3.4.2 build
5月 03 12:15:37 ls.leafia.net yarn[186333]: > node build.js
5月 03 12:15:37 ls.leafia.net yarn[186345]: [Ackee] › … awaiting Building and writing 'dist/index.html'
5月 03 12:15:37 ls.leafia.net yarn[186345]: [Ackee] › ✔ success Finished building 'dist/index.html'
5月 03 12:15:38 ls.leafia.net yarn[186356]: > ackee@3.4.2 server
5月 03 12:15:38 ls.leafia.net yarn[186356]: > node src/index.js
5月 03 12:15:40 ls.leafia.net yarn[186368]: Persisted queries are enabled and are using an unbounded cache. Your server is vulnerable to denial of service attacks via memory exhaustion. Set `c>
5月 03 12:15:40 ls.leafia.net yarn[186368]: [Ackee] › … awaiting Connecting to http://mongodb+srv/ackee:password@db.leafia.net/ackee
5月 03 12:15:40 ls.leafia.net yarn[186368]: (node:186368) [MONGOOSE] DeprecationWarning: Mongoose: the `strictQuery` option will be switched back to `false` by default in Mongoose 7. Use `mong>
5月 03 12:15:40 ls.leafia.net yarn[186368]: (Use `node --trace-deprecation ...` to show where the warning was created)
```