Debug/Diagnostic color is far too dark

While investigating issues with https://github.com/cake-build/cake/pull/3240, I temporarily enabled Debug/Diagnostic logging for the integration tests, during which the log rendering is far too dark and becomes unreadable in some environments.

GitHub Actions run 2052071902:

Azure Pipelines build 17082:

Here's another screenshot of a normal GitHub Actions run showing the color spectrum for different LogLevel/Verbosity:

And the same for a normal Azure Pipelines build:

Finally, I've seen similar problems when building local in WSL.