Revert "Install build dependencies for Python 3.6"

This reverts commit 13447fd.

Author: qykth-git

.github/workflows/main.yml

@@ -19,7 +19,6 @@ jobs:
       uses: fedora-python/tox-github-action@main
       with:
         tox_env: ${{ matrix.tox_env }}
-        dnf_install: gcc libxml2-devel libxslt-devel
     strategy:
       matrix:
         tox_env: