API version should be a configuration

API version is currently hard coded in the tap (https://gitlab.com/meltano/tap-salesforce/-/blob/master/tap_salesforce/salesforce/init.py#L212) This should be a configuration option.

Impact: I noticed I was missing fields in my replication of Salesforce records. This was fundamentally caused by the api version being too low for the field I wanted to replicate.