fix: convert SecretStr to Str when update

[anancarv]

Description

Remote repository update fails with Object of type 'SecretStr' is not JSON serializable. It is because we do not convert the SecretStr to Str when making the API call to the artifactory API.

Fixes #99

Type of change

• [x] Bug fix (non-breaking change which fixes an issue)

Checklist:

• [x] My PR is ready for prime time! Otherwise use the "Draft PR" feature
• [x] All commits have a correct title
• [x] Readme has been updated
• [x] Quality tests are green (see Codacy)
• [x] Automated tests are green (see pipeline)