fix: pin event-tracking for pymongo 4.4.0 support

[Ian2012]

Description:

Pins event-tracking to a version before installing pymongo 4.4.0 which is not supported on edx-platform.

See https://github.com/openedx/tutor-contrib-aspects/issues/891, https://github.com/openedx/event-routing-backends/pull/436, https://github.com/openedx/completion/pull/305 for more information.

Merge checklist:

• [ ] All reviewers approved
• [ ] CI build is green
• [ ] If adding new checks, followed how_tos/0001-adding-new-checks.rst
• [ ] Changelog record added (if needed)
• [ ] Documentation updated (not only docstrings) (if needed)
• [ ] Commits are squashed