Why are these changes needed?

devcontainer needs an update on the dependencies to run the coverage and parallel test execution with pytest

Related issue number

[ ] I've included any doc changes needed for https://autogen-ai.github.io/autogen/. See https://autogen-ai.github.io/autogen/docs/Contribute#documentation to build and test documentation locally.
[ ] I've added tests (if relevant) corresponding to the changes introduced in this PR.
[x] I've made sure all auto checks have passed.