v0.6.3

MultivariateOrthogonalPolynomials v0.6.3

Diff since v0.6.2

Merged pull requests:

• CompatHelper: bump compat for DomainSets to 0.7, (keep existing compat) (#167) (@github-actions[bot])
• Add weaklaplacian (#168) (@dlfivefifty)
• Support plotting on rectangles (#169) (@dlfivefifty)