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.