Osidb-bindings

Added
- Update and Create for Tracker entity
- JIRA_ACCESS_TOKEN environment variable

Fixed
- Both Bugzilla API Key and Jira Access Token are now automatically fetched
from environment variables and passed as a header

Fixed
- add workaround for Erratum shipped_dt which is marked as non-nullable
despite being nullable

Added
- add CRUD operations for Flaw CVSS scores and
package version and for Affect CVSS scores

Fixed
- removed leftover debug output

Fixed
- fix regression in `to_dict` introduced in 3.4.4 by
fliped condition