Use a copy of the now defunct sath89/oracle-12c image.

[charettes]

https://hub.docker.com/r/truevoly/oracle-12c

Fixes #4

[martsberger]

This change gets passed the error in issue #4, docker-compose run --rm oracle-db works correctly.

But running this branch I get the following error during docker-compose run --rm oracle:
/oracle_entrypoint.sh: line 7: sudo: command not found

Which is really odd, I can't imagine what environment would not have sudo as a command.

Edit: So, it makes sense to me to merge this PR and open another issue for the above (if anyone else is having it, or if I'm just doing something wrong, that would be great)

[laymonage]

@martsberger I'm also having the same issue using the official image from Oracle. It looks like the Debian distribution that comes with Python slim image doesn't have sudo. However, if you install it, it will ask for the test user's password, which actually isn't set. I don't know what would be the best way to configure the instantclient with this permission issue 🤷‍♂️