Dependabot updates require rebase every time Verify and Verify.Xunit pair has an update

[zengin]

Verify is a transitive dependency through Verify.Xunit and they receive updates from dependabot to same version numbers each time. However, the PR for Verify.Xunit fails unless Verify PR is checked in first and then Verify.Xunit one is rebased.

Examples:
The #918 and #919 pair.
The #901 and #902 pair.

Not being able to configure this in dependabot is a known issue which seems to be around quite a while and is not yet addressed:

• Ability to combine PR's via a dependabot comment dependabot/dependabot-core#2652
• Support grouping for "must-be-updated-together" dependencies dependabot/dependabot-core#1296

I think we can resolve it in this repo by referring to Verify.Xunit explicitly in csproj and letting nuget restore to fetch corresponding Verify library by transitivity. That should reduce the number of dependabot PRs and the need to manually order and rebase them.