CompatHelper: bump compat for BandedMatrices to 1, (keep existing compat)

[github-actions[bot]]

This pull request changes the compat entry for the BandedMatrices package from 0.16,0.17 to 0.16,0.17, 1. 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.