CompatHelper: bump compat for "DomainSets" to "0.4" (#136)

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: Sheehan Olver <solver@mac.com>

Author: github-actions[bot]

Project.toml

@@ -24,7 +24,7 @@ ApproxFunFourier = "0.2"
 ApproxFunOrthogonalPolynomials = "0.3"
 ApproxFunSingularities = "0.1.6, 0.2"
 BandedMatrices = "0.14.2, 0.15, 0.16"
-DomainSets = "0.1, 0.2, 0.3"
+DomainSets = "0.1, 0.2, 0.3, 0.4"
 DualNumbers = "0.6"
 HypergeometricFunctions = "0.1, 0.2, 0.3"
 LowRankApprox = "0.4"