fix faiss-gpu nightly

Summary: Forcing cudatoolkit to 11.8 to work around cudatoolkit vs cuda-cudart clobbering: https://app.circleci.com/pipelines/github/facebookresearch/faiss/4845/workflows/baee8356-31c5-44e8-ae98-44f897967557/jobs/26451?invite=true#step-105-335068_80

Reviewed By: mlomeli1

Differential Revision: D50924919

fbshipit-source-id: 590f39d1292ec64af7e179e764b8e7ac26108962

conda/faiss-gpu/meta.yaml

@@ -89,6 +89,7 @@ outputs:
         - scipy
         - pytorch
         - pytorch-cuda =11.8
+        - cudatoolkit =11.8
       commands:
         - python -X faulthandler -m unittest discover -v -s tests/ -p "test_*"
         - python -X faulthandler -m unittest discover -v -s tests/ -p "torch_*"