Acknowledge testing dependencies in pyproject.toml

[jesper-friis]

PR EMMC-ASBL/tripper#52 fails due to external CI/CD tests implemented in this repo.

See issue EMMC-ASBL/tripper#48 for a motivation for the failing PR.

The only change in the PR was to move some optional dependencies from dependencies to testing in pyproject.toml.
Since this is a testing framework, it should acknowledge testing dependencies.

[CasperWA]

It's up to the given repository that uses ci-cd to parse the correct extra installations: https://sintef.github.io/ci-cd/latest/workflows/ci_tests/#run-pylint-safety https://sintef.github.io/ci-cd/latest/workflows/ci_tests/#build-mkdocs-documentation

Here I've linked the documentation for the tests that seems to fail in your link.

Since this is not an issue of this repository, I am closing this issue. One should however probably be opened and fixed in your repository.