Replace conflict strategy does not update PR body

[andyren0110]

Describe the bug
I ran multi-gitter once to create some PRs.
Later I wanted to update the body of the PR by changing the value of -b but it does not upgrade the content of the PR.

To Reproduce
Steps to reproduce the behavior:
multi-gitter run -O -m "message" -B branch -b "some body"
multi-gitter run -O -m "message" -B branch --conflict-strategy replace -b "some other body"

PR body remains "some body"

Expected behavior
Expect the PR body to change to "some other body"

Additional context
Add any other context about the problem here.
It is for example often useful to include detailed logs from a run with --log-level=trace.

[lindell]

Not a bug per se, since it has not been intended to do that

Replace the existing content of the branch by force pushing any new changes, then reuse any existing pull request, or create a new one if none exist.

But it could definitely be added, but that would also have to be true for all fields of a PR, like reviewers, title, draft status, etc.
I will not prioritize this myself but would happily merge a PR where this is added.

Until then, closing all PRs and running it again might suffice.