Describe the bug
We're running auto manually because we batch PRs into a release. It's a high moving project so we might have 10s of releases a day if it was through CI. Using versionBranch in the config, a new branch is created on a major release. Super cool! But comparing that branch to the corresponding release tag shows a ton of extra changes that should only be in the current release.

To Reproduce

Not using auto in a CI environment. "versionBranches": "release/"

• Merge multiple PRs to master, one of them being a breaking change (all of these will become v2.0)
• Manually run auto shipit making a 2.0 release and a new version branch is created (release/1)
• Compare previous release tag (v1.0) to newly created release branch release/1

The release branch contains the merged PRs that should only be in 2.0

Expected behavior

My guess is that the version branch is created from the state right before the command is run. In our case, we have a handful of PRs that are on master that haven't been released yet waiting to go out in a batch, and all of those get pushed to the new version branch.

I would expect that, since we're already looking back in history at the latest release (v1.0 tag), that tag would be used for content of the version branch instead.

Screenshots

Environment information:

"auto" version: v9.52.0
"git"  version: v2.28.0
"node" version: v12.19.0

Additional context