pulp-cli passing an extra argument when modifying a repo

[YasenT]

Summary

When modifying a repository, by adding content for example, pulp-cli passes base_version to the api, which is optional and shouldn't be used by default. The end result is that when doing few concurrent modifications to the repo -> they overwrite each other, as each is pointing to the same base_version

Steps to reproduce

pulp --domain domain-name rpm repository content modify --add-content '[{"pulp_href": "some-href"}]' --repository repo-name

Expected behavior

Stacktrace/Error log

Pulp and pulp-cli version info

Additional context