add tests for Float32

[stevengj]

Just wrap all tests in

for T in (Float32, Float64), n in (....)
   A = skewhermitian!(rand(T), n, n)
   ...
end

and maybe add some type assertions like eigvals(A)::Vector{Complex{T}} ≈ [....]

[stevengj]

Thanks! In general, I would suggest closing issues from a PR (just put closes #39 in the description of the PR), or at least from commits (put closes #39 in the commit message) if you are pushing the commits directly.

[stevengj]

Looking at https://github.com/smataigne/SkewLinearAlgebra.jl/blob/main/test/runtests.jl, I don't see any tests for Float32. Did you close this by accident?