Git-machete

- fixed: automatic updates of Homebrew formula

- fixed: deployment issues

- added: `-f`/`--as-first-child` flag to `git machete add` (contributed by matthalp)
- fixed: `git machete github retarget-pr` not updating description of PR due to stray `\r` characters

- fixed: make fork-point also take into account common ancestors (and not only reflogs) in more cases

- fixed: if a PR has a pre-v3.23.0 `Based on PR ...` header, then it's removed by `git machete github retarget-pr` in favor of the new extended PR chain

- added: full chain of PRs (and not just a link to the base PR) is added to/updated in PR description by `git machete github create-pr`/`retarget-pr`/`restack-pr` (suggested by mjgigli)
- fixed: in the unlikely case of a cycle between GitHub PRs, `git machete github checkout-pr` aborts with an error rather than falling into an infinite loop
- fixed: when checking out longer PR chains, `git machete github checkout-prs` prints out all checked out branches correctly