MAINT: removed some Python3.6-specific code

Author: gdementen

.github/workflows/python-package-conda.yml

@@ -28,8 +28,6 @@ jobs:
         auto-update-conda: true
         environment-file: environment.yml
         python-version: ${{ matrix.python-version }}
-    - run: pip install dataclasses
-      if: ${{ matrix.python-version == 3.6 }}
     - run: conda info
     - run: conda list
     - run: conda config --show