ci: remove python-updates from development branches

The python-updates branch is not a "development" branch in the sense of
ci/README.md's classification. That's because it allows force pushes.
When rewrites are possible, cherry-picking from this branch should not
be allowed, because the commit references will potentially end up out of
sync.

These kind of branches are now termed "Work-in-Progress" branches. Up
until recently these branches didn't work well for Pull Requests
targeting them, because Eval wouldn't run on them with a push event and
thus, Eval in the PR couldn't succeed either. That's now fixed, PRs
towards *any* WIP branch should work correctly.

Changed files
+1 -4
.github
workflows
ci
-1
.github/workflows/push.yml
···
- release-*
- staging-*
- haskell-updates
-
- python-updates
permissions: {}
+1 -1
ci/README.md
···
- Pull Requests required.
- Long-lived, no deletion, no force push.
- **Secondary development** branches
-
- `staging-` prefix, `haskell-updates` and `python-updates`
+
- `staging-` prefix and `haskell-updates`
- Pull Requests normally required, except when merging development branches into each other.
- Long-lived, no deletion, no force push.
- **Work-In-Progress** branches
-1
ci/request-reviews/dev-branches.txt
···
release-*
staging-*
haskell-updates
-
python-updates
-1
ci/supportedBranches.js
···
staging: ['development', 'secondary'],
'staging-next': ['development', 'secondary'],
'haskell-updates': ['development', 'secondary'],
-
'python-updates': ['development', 'secondary'],
nixos: ['channel'],
nixpkgs: ['channel'],
}