Try pip

.github/workflows/python-package.yml

@@ -31,9 +31,7 @@ jobs:
       shell: bash -l {0}
       run: |
         conda install -c conda-forge pymultinest
-        pip install nestle
-        conda install pip pytest
-        pip install .[QUfitting,parallel] --upgrade
+        pip install -U .[QUfitting,parallel] nestle pytest
     - name: Test with pytest
       shell: bash -l {0}
       run: |