A prettier version bump changes prettier's canonical output, so files
that were correctly formatted under the old version now fail
`prettier --check` in CI — the update PR goes red and never automerges.
This happened on castaway with prettier 3.8.3 -> 3.9.6 (two files
reformatted: a union type collapsed to one line, a Svelte closing tag
pulled onto the attribute line).
Add a npm-scoped postUpgradeTasks that runs `npm run format` once per
branch after the upgrade and commits the result. `--if-present` makes it
a no-op in npm repos without a format script; matchManagers npm keeps it
away from the gradle/maven and firmware repos that share this preset.
Requires the self-hosted Renovate instance to whitelist the command via
allowedCommands (e.g. RENOVATE_ALLOWED_COMMANDS='^npm run format') — that
is a global/self-hosted-only option and cannot be set from this preset.
Signed-off-by: Peter Siegmund <peter.siegmund@entwicklung.eq-3.de>
