CompatHelper: bump compat for Interpolations to 0.16, (keep existing compat)

[github-actions]

This pull request changes the compat entry for the Interpolations package from 0.9, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15 to 0.9, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16.
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.

[lukem12345]

I updated Interpolations locally and ran ]test and it looks good to me:

Precompiling project for configuration --code-coverage=none --color=yes --check-bounds=yes --warn-
overwrite=yes --depwarn=yes --inline=yes --startup-file=no --track-allocation=none...
  2 dependencies successfully precompiled in 3 seconds. 96 already precompiled.
     Testing Running tests...
Running tests:
 * univariate.jl
 * bivariate.jl
 * interp.jl
┌ Warning: `MvNormal(d::Int, σ::Real)` is deprecated, use `MvNormal(LinearAlgebra.Diagonal(FillArr
ays.Fill(σ ^ 2, d)))` instead.
│   caller = ip:0x0
└ @ Core :-1
     Testing KernelDensity tests passed

(KernelDensity) pkg> st
Project KernelDensity v0.6.9
Status `~/Code/KernelDensity.jl/Project.toml`
  [31c24e10] Distributions v0.25.120
  [ffbed154] DocStringExtensions v0.9.4
  [7a1cc6ca] FFTW v1.8.1
  [a98d9a8b] Interpolations v0.16.0
  [2913bbd2] StatsBase v0.34.5

[fhagemann]

This PR also supersedes #115, once merged.

[cgarling]

This would be great to merge!

[cgarling]

@tpapp could you merge this?

In the future I would be happy to take care of small maintenance items like this if you'd like to grant me merge permissions. I'm currently a maintainer for the JuliaAstro org.

[tpapp]

Happy to merge, but since I am not the owner I am not able to grant you permissions.

[cgarling]

Gotcha, thanks!