Add new Eigen versions 5.0.0 and 3.4.1

[jcortial-safran]

The long-awaited new Eigen releases are there !

See the release notes :

• https://gitlab.com/libeigen/eigen/-/releases/5.0.0
• https://gitlab.com/libeigen/eigen/-/releases/3.4.1

@HaoZeke: Since you are the package maintainer, I let you the initiative to start a PR, unless you are ok with xomeone elseto do it.