RFC: 5.0 release

[totallyzen]

Context

With the new release pipeline now working, we're discovering more things we want to fix.
Some of these are arguably breaking changes to the previously established API.
Instead of trying to keep patching issues via workarounds, some changes are better done via a breaking change and updated user documentation on how to upgrade.

Known Issues

• Most other Testcontainers implementations use Ryuk, which is responsible for preventing leaking containers in case of failure or instability - an implementation was started in feat(reliability): integrate the ryuk container for better container cleanup #314 and potentially is another reason for a breaking change
• We surfaced in fix(postgres): Remove SqlAlchemy dependency from postgres container #445 that the way DbContainer works is a bit awkward and potentially want to improve all containers in what guarantees all classes give (via a proper ABC)
  • Guaranteed readiness implementation
  • Easy configuring of the container (with strong semantically correct types)
  • Prefer credentials over connectivity clients

Request For Comment

Of course we're not immune to mistakes, your input is valuable in understanding how people use the library and why se should or should not change how things work.

FYI @santi for the issue and planning 🙂

[totallyzen]

since we resolved most recent issues within 4.x, I'm closing this issue. See the other issue for details