CompatHelper: bump compat for Makie to 0.20, (keep existing compat)
This pull request changes the compat entry for the Makie
package from 0.19
to 0.19, 0.20
.
This keeps the compat entries for earlier versions.
Note: I have not tested your package with this new compat entry. It is your responsibility to make sure that your package tests pass before you merge this pull request.