Now `tox -e docs` will also include the draft changelog for the next version (locally only). `CHANGELOG.rst` now only points to the changelog on READTHEDOCS so sphinx diretives can be used. Followup to https://github.com/pytest-dev/pytest/pull/6272
Fix #1274
Signed-off-by: Abhijeet Kasurde <akasurde@redhat.com>