eigen 5 support

[nim65s]

Hi,

In order to fix support for eigen 5 in pinocchio 3 (stack-of-tasks/pinocchio#2779), we'll need to fix support for eigen 5 in proxsuite first.

My initial try fail with:

proxsuite> The following tests FAILED:
proxsuite>       66 - ProxQP::dense: test primal infeasibility solving (Failed)
proxsuite>      142 - dense maros meszaros using the api (Timeout)
proxsuite>      143 - sparse maros meszaros using the API (Timeout)