Remove scipy conda package before pip installing in unstable CI

.github/workflows/ci.yaml

@@ -43,6 +43,7 @@ jobs:
         shell: bash -l {0}
         run: |
           python -m pip install versioneer; \
+          conda uninstall --force-remove -y scipy; \
           python -m pip install \
           -f https://pypi.anaconda.org/scientific-python-nightly-wheels/simple/ \
           --trusted-host pypi.anaconda.org \