Replace username by user in Mongo Client connection options

[juananpe]

According to the API docs for Mongo Client connection options:
https://api.mongodb.com/ruby/current/Mongo/Client.html#initialize-instance_method:~:text=characters-,.,%3A
the correct value for specifying the username of the connection string is user, not username.

Trying to log to mongo using "username" instead of "user" will yield the following error:

ERROR Logging failed: https://domain.com - there are no users authenticated (13) (on localhost, legacy retry, attempt 1)

It is also more clearly highlighted when using --debug option in whatweb:

W, [2020-11-25T22:02:15.304776 #262609] WARN -- : MONGODB | Unsupported client option 'username'. It will be ignored.

The attached patch allows to connect using authentication options and insert logs into mongo without problems:

./whatweb -p +./plugins-disabled/charset.rb --log-mongo-host localhost --log-mongo-database whatwebdb --log-mongo-username yyyyyyy --log-mongo-password xxxxxxx https://domain.com

[urbanadventurer]

Thanks @juananpe. It LGTM!