CompatHelper: bump compat for "Pluto" to "0.17"

[github-actions[bot]]

This pull request changes the compat entry for the Pluto package from 0.12.21, 0.14 to 0.12.21, 0.14, 0.17.

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.