Add a check to see if the Conjur version is out of date

[telday]

Is your feature request related to a problem? Please describe.

The new RetreieveBatchSecretsSafe method requires at least Conjur version 1.11.4 or above. We should have a check which either warns the user or shows an error if the Conjur version is older.

[szh]

This is handled in the response if the secrets come back not encoded:
https://github.com/cyberark/conjur-api-go/blob/main/conjurapi/variable.go#L113-L118
While we could do a proactive check before sending the request, as we do with policy dry run, there's less of a need here since there's no destructive action if it fails.