v0.6.20

ApproxFunOrthogonalPolynomials v0.6.20

Diff since v0.6.19

Merged pull requests:

• Use == for Integer in spacescompatible (#218) (@jishnub)
• Add dependabot (#219) (@jishnub)
• Chebyshev check in Jacobi conversion (#220) (@jishnub)
• simplify chebyshev/ultraspherical conversions (#221) (@jishnub)
• condense show space methods (#222) (@jishnub)
• accept numbers as integral orders (#223) (@jishnub)