CompatHelper: bump compat for Polynomials to 4, (keep existing compat) (#77)

Co-authored-by: CompatHelper Julia <compathelper_noreply@julialang.org>

Author: github-actions[bot]

Project.toml

@@ -53,7 +53,7 @@ MultivariateStats = "0.7, 0.8, 0.9, 0.10"
 NaNMath = "0.3, 1"
 Optim = "1"
 PDMats = "0.10, 0.11"
-Polynomials = "1, 1.1, 2, 3"
+Polynomials = "1, 1.1, 2, 3, 4"
 ProgressMeter = "1.4"
 QuadGK = "2.4"
 Query = "1"