Fix the way the current version is checked on CD

.github/workflows/pythonpublish.yaml

@@ -25,7 +25,7 @@ jobs:
           python --version
       - name: Check current package version
         run: |
-          python setup.py --version
+          python -c "import pangeo_forge_esgf; print(pangeo_forge_esgf.__version__)
       - name: Build tarball and wheels
         run: |
           git clean -xdf

pangeo_forge_esgf/__init__.py

@@ -2,6 +2,11 @@
 import logging
 import backoff  # noqa #https://github.com/litl/backoff/issues/71
 
+try:
+    from ._version import __version__
+except ImportError:
+    __version__ = "unknown"
+
 logging.getLogger("backoff").setLevel(logging.FATAL)
 # not sure if this is needed, but I want to avoid the many backoff messages