build(deps): bump psycopg2 from 2.8.5 to 2.8.6 in /src/karmen_backend

Bumps [psycopg2](https://github.com/psycopg/psycopg2) from 2.8.5 to 2.8.6.
- [Release notes](https://github.com/psycopg/psycopg2/releases)
- [Changelog](https://github.com/psycopg/psycopg2/blob/master/NEWS)
- [Commits](https://github.com/psycopg/psycopg2/commits)

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