* Suppress all warnings when running `otter.check.validate_export` as a module per [735](https://github.com/ucbds-infra/otter-grader/issues/735)
* Updated default version of `ottr` to v1.5.0
* Added a way to exclude Conda's defaults channel from autograder `environment.yml` files in Otter Assign and Otter Generate per [778](https://github.com/ucbds-infra/otter-grader/issues/778)