Pin `detectron2` for CircleCI tests
# What does this PR do?

The commit `36a65a0907d90ed591479b2ebaa8b61cfa0b4ef0` in `detectron2 ` break things, see [here](https://github.com/facebookresearch/detectron2/commit/36a65a0907d90ed591479b2ebaa8b61cfa0b4ef0#comments).

Ping the parent commit until that issue is fixed.

Issue found by @amyeroberts 
_The documentation is not available anymore as the PR was closed or merged._<|||||>Merge now to avoid  CI failure on PRs.