Duplicate PRs for weakdeps

[jishnub]

See JuliaApproximation/ApproxFunOrthogonalPolynomials.jl#350 and JuliaApproximation/ApproxFunOrthogonalPolynomials.jl#349, which are basically the same change, but two PRs are created as the package is listed both under [deps] and [weakdeps].

The project.toml: https://github.com/JuliaApproximation/ApproxFunOrthogonalPolynomials.jl/blob/c91c8d53ff565e95ac86949c0477fc698dcc72af/Project.toml