Monorepo flow: Roll back all filesystem changes if error encountered

It is possible for an error to occur while making changes to a monorepo. For instance, as we are updating the changelog for each package, `auto-changelog` will call `git fetch --tags` to get the latest tags for the repo. Admittedly, it should probably only do this once at the beginning, but regardless, if this fails for a particular package, but we have made changes to other packages, then the tool will completely abort and leave the repo in a dirty state. We should see if we can roll back all of the filesystem changes if this occurs.

Start by tracing the monorepo release flow that updates each package's changelog and invokes auto-changelog, including its git fetch --tags call. Define the failure path and verify that an error after earlier package changes leaves the filesystem unchanged; the issue does not mention specific files or tests.

Written by the indexing model from the issue text.