Make the GCP PubSub container work

[hy9be]

Accidentally closed the PR under review https://github.com/testcontainers/testcontainers-python/pull/183 and cannot reopen it. Recreated this one.

Changes

• Replace with_exposed_ports with with_bind_ports
• Modify the context manager to set and unset environment variable as mentioned in https://cloud.google.com/pubsub/docs/emulator#env
• Update the test
• Update the pubsub gcp lib versions

[tillahoffmann]

Thanks for the updated PR! It looks like it is reverting a number of changes introduced in previous work, e.g the docker version from #203 or clickhouse support from #173. This may be the result of copying code from an outdated branch. That's also the reason for early test failures.

[hy9be]

Yeah, I think you are right. I will take a look.