CompatHelper: bump compat for DistributedFactorGraphs to 0.26, (keep existing compat)

[github-actions[bot]]

This pull request changes the compat entry for the DistributedFactorGraphs package from 0.22, 0.23, 0.24 to 0.22, 0.23, 0.24, 0.26. 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.