add multiple test container example

[akoserwal]

Related Issue or Design Document

Hi Team, I create a blog guide on creating multiple dependent test containers using the docker test library with code examples. Work around for issue: #511

https://akoserwal.medium.com/creating-multiple-test-containers-with-ory-dockertest-in-go-5b8311614e7b

If you think this example is good, then we can add it.

Checklist

• I have read the contributing guidelines and signed the CLA.
• I have referenced an issue containing the design document if my change introduces a new feature.
• I have read the security policy.
• I confirm that this pull request does not address a security vulnerability.
  If this pull request addresses a security vulnerability,
  I confirm that I got approval (please contact security@ory.sh) from the maintainers to push the changes.
• I have added tests that prove my fix is effective or that my feature works.
• I have added the necessary documentation within the code base (if appropriate).

Further comments

[CLAassistant]

All committers have signed the CLA.