CI: fix nightly-deps env so nightlies of all relevant dependencies are used (#529)

Because geopandas-base is being installed via conda-forge, all it's dependencies (numpy, geopandas, shapely) are also already being installed from standard conda-forge. Because they are already installed when pip kicks in, the nightlies from scientific-python-nightly-wheels aren't actually installed...

This PR changes the env so geopandas is also installed via pip, which solves above issue.

Author: theroggy

ci/envs/nightly-deps.yml

@@ -5,10 +5,10 @@ channels:
 dependencies:
   - libgdal-core
   - pytest
-  - geopandas-base
   - pip
   - pip:
     - --pre --prefer-binary --index-url https://pypi.anaconda.org/scientific-python-nightly-wheels/simple --extra-index-url https://pypi.fury.io/arrow-nightlies/ --extra-index-url https://pypi.org/simple
+    - geopandas
     - numpy>=2.0.0.dev
     - shapely
     - pandas