Fix branching automation: create `1.10.x` branch, rename `1.9.x` to `1.10.x`, reset `1.9.x` to `1.9.0`

[Ocramius]

Automation failed to create 1.10.x and switch default branch to it (https://github.com/Roave/you-are-using-it-wrong/runs/1735873530?check_suite_focus=true)

We need to fix that:

1. 1.9.x contains improvements that shouldn't be there: rename it to 1.10.x
2. reset 1.9.x to 1.9.0 (and force-push)
3. release 1.10.0 and verify that 1.11.x is the new default branch.