Collapse history 2020

[jaraco]

This skeleton project has had a single line of development with 207 commits. There's no way to collapse these commits for projects that have already merged them, but for future projects, this long history becomes more and more burdensome to adopt.

To that end, I've decided to do a periodic squash.

I created a new branch, archive/2020-12 to keep those commits and reset the mastermain branch to point to c681f67 (currently a single commit).

For convenience, I've also created a 2020-handoff branch to ease the transition and automate the reconciliation of these two branches for any repos already based on the commits in archive/2020-12.

[jaraco]

As I'm doing this again, I want to document the steps necessary to create the collapse:

git push origin HEAD:archive/YYYY-MM
git checkout --orphan collapse
git commit -m "Collapse skeleton history from archive/YYYY-MM"
git checkout origin/archive/2023-07
git merge --allow-unrelated-histories --no-edit collapse
git push origin HEAD:2023-handoff
git checkout main
git reset --hard collapse
git branch -d collapse
git push -f