ci: add libarchive to dependencies

This is needed to work around a bug in conda.

Author: indygreg

.github/workflows/anaconda.yml

@@ -37,6 +37,9 @@ jobs:
           source $CONDA/bin/activate env
           $CONDA/bin/conda install --yes --quiet --name env conda-build pip
           pip install --require-hashes -r ci/requirements.txt
+          
+          # libarchive is required as a workaround for https://github.com/conda/conda-build/issues/4835
+          pip install libarchive
 
       - name: Build and Test
         run: |