Avoid warning for inter-relative extra dependencies

[CasperWA]

In the update-deps task, there is no need to warn if an inter-relative extra dependency is found, e.g.:

[project]
name = "ci-cd"

[project.optional-dependencies]
testing = ["pytest", "pytest-cov"]
dev = ["pre-commit", "ci-cd[testing]"]

Here, the ci-cd[testing] dependency should be ignored.