Update Salesforce SOAP API Connector to at least v44

So, following up from this comment from over two years ago, I'd like to see the Marketo-Salesforce SOAP API connection upgraded to v44. Why?

- There is a ton of future work I can see doing with the Individual object as it gets more fleshed out into a fully-formed Lead-Contact junction object.

- Likewise, I think there's a lot of potential with UserEmailPreferredPerson and solving some of the pain points that intentional-duplicating orgs have.

- Although I myself don't have any current clients that would benefit from this, a lot of the new Partner objects would be great for those who sell with the assistance of partners and brands.

Also, AccountRelationship seems useful and cool.