Fix release train dependencies and change colors

[So-Fras]

Please check if the PR fulfills these requirements

• [x] The commit message follows our guidelines

What kind of change does this PR introduce? Bug fix

What is the current behavior? There is a missing dependency in the release train diagram.

What is the new behavior (if this is a feature change)? The release train diagram is fixed and a new set of colors is also suggested.

Does this PR introduce a breaking change or deprecate an API?

• [ ] Yes
• [x] No