try commenting use only tar bz2

.github/workflows/unittest.yml

@@ -45,7 +45,7 @@ jobs:
           channels: conda-forge,defaults
           mamba-version: "*"
           environment-file: environment.yml
-          use-only-tar-bz2: true # IMPORTANT: This needs to be set for caching to work properly!
+          # use-only-tar-bz2: true # IMPORTANT: This needs to be set for caching to work properly!
           #   These don't seem to be valid options for this action
           #   See: https://github.com/conda-incubator/setup-miniconda
           # cache-environment-key: ${{ runner.os }}-env-${{ hashFiles('**/environment.yml') }}