Bump aind-flake8-extensions to 0.6

[dbirman]

User story

As a user I want to be warned that I should be using AwareDatetimeWithDefault instead of datetime. Updating to aind-flake8-extensions>=0.6 would make this happen, but this causes problems because the base class uses datetime directly

Acceptance criteria

• [ ] aind-flake8-extensions>=0.6 in pyproject.toml and all tests pass

Sprint Ready Checklist

• [ ] 1. Acceptance criteria defined
• [ ] 2. Team understands acceptance criteria
• [ ] 3. Team has defined solution / steps to satisfy acceptance criteria
• [ ] 4. Acceptance criteria is verifiable / testable
• [ ] 5. External / 3rd Party dependencies identified
• [ ] 6. Ticket is prioritized and sized