FYI: alternative implementations

[aspiers]

This is not an issue, so feel free to close straight away, but I thought you might be interested to know about my alternative implementation:

• https://github.com/aspiers/git-deps/blob/master/bin/git-fixup
• https://github.com/aspiers/git-deps/blob/master/USE-CASES.md#use-case-4-automatic-squashing-of-fixup-commits

There are others too:

• https://github.com/tummychow/git-absorb - written in Rust, doesn't use blame, only searches 10 most recent commits by default
• https://github.com/torbiak/git-autofixup - written in Perl, uses blame