Add cxx interop build pipeline

[gjcairo]

This PR adds a new target to docker-compose that builds this project with C++ interoperability enabled, with the goal of adding a new CI pipeline that performs this check.

Motivation:

To make sure that C++ interoperability can be used on projects that depend on swift-crypto.

Modifications:

• Added a new target to docker-compose that builds this project with C++ interoperability enabled.
• Will request a new CI pipeline that runs this new target.

Result:

We will ensure this projects builds properly with C++ interoperability enabled.

[gjcairo]

@yim-lee would you mind setting up a new pull request validation (cxx interop) pipeline that runs the new target?

[yim-lee]

Need to add cxx-interop-build to docker-compose.2204.59.yaml etc. to override image.

I updated docker-compose.2204.59.yaml in 6667d11

[yim-lee]

@swift-server-bot add to allowlist

[yim-lee]

@gjcairo I added new pipeline pull request validation (cxx interop) pipeline as requested. It uses Swift 5.9, similar to "api breakage" and "cmake" pipelines. We can set up separate "cxx interop" pipelines for Swift 5.9 and 5.10 if you want. Just let me know.

[yim-lee]

@swift-server-bot test this please

[gjcairo]

Thanks @yim-lee ! I had to make some changes to the step so hopefully it all still works :D
I think it would make sense to have a pipeline for 5.10 in this case, as I suppose things related to the interoperability may change between Swift versions and we want to make sure we are still green with newer versions. Would you mind setting up a second pipeline? I have updated the corresponding docker-compose file for 5.10 too.

[yim-lee]

CI updated. "5.9 cxx interop" and "5.10 cxx interop" replaced "cxx interop".

@swift-server-bot test this please