try evaling the bash hook

per https://github.com/conda/conda/issues/7980

.github/workflows/pr-checks.yaml

@@ -37,11 +37,13 @@ jobs:
       - name: Build environment
         run: |
           conda env create -f environment.yml
+          eval "$(conda shell.bash hook)"
           conda activate cellxgene-gateway
           python setup.py install
 
       - name: Run tests
         run: |
+          eval "$(conda shell.bash hook)"
           conda activate cellxgene-gateway
           python -m unittest discover tests
           bash <(curl -s https://codecov.io/bash)