Issue #714/#717 best effort geopandas support on python 3.8

Author: soxofaan

setup.py

@@ -25,7 +25,10 @@
     "urllib3<2.3.0",  # httpretty doesn't work properly with urllib3>=2.3.0. See #700 and https://github.com/gabrielfalcao/HTTPretty/issues/484
     "netCDF4>=1.7.0",
     "matplotlib",  # TODO: eliminate matplotlib as test dependency
-    "geopandas>0.13.2",
+    # TODO #717 clean up geopandas constraints when Python 3.8 support is dropped:
+    #      #714 requires >0.13.2, but that does resolve for Python 3.8
+    "geopandas>0.13.2; python_version>='3.9'",
+    "geopandas",
     "flake8>=5.0.0",
     "time_machine",
     "pyproj>=3.2.0",  # Pyproj is an optional, best-effort runtime dependency