`eigmin`/`eigmax` for `Eigen`?

[longemen3000]

In my opinion, the following methods on LinearAlgebra.Eigen are missing:

• eigmin(eig::Eigen)
• eigmax(eig::Eigen)

We already define eigvals(eig::Eigen), so those two are trivial to define.

[Luis-Varona]

Hi, @longemen3000 and @ViralBShah - I've created PR #1468 to hopefully address this. 🙂