modify ops to have kw only set up (e.g. add the '*')

[zzzeek]

we likely have to modify tools/write_pyi to handle this, autogenerate is likely OK and the change here is probably warranting of a bigger release bump. But we should guard against issues like #1127 and we should have done this when we released for Python 3.

[sqla-tester]

Mike Bayer has proposed a fix for this issue in the main branch:

wip: keyword only arguments in ops https://gerrit.sqlalchemy.org/c/sqlalchemy/alembic/+/4238

[zzzeek]

not ready to do this for now, want to get 1.9 out with the new alembic check feature

[sqla-tester]

Mike Bayer has proposed a fix for this issue in the main branch:

add a few more kw only https://gerrit.sqlalchemy.org/c/sqlalchemy/alembic/+/4614