fix(ci): don't let the uncommitted npm bump abort the plugin version sync

[JonasJesus42]

#339 shipped broken. The Sync plugin version step committed, then died on:

error: cannot pull with rebase: You have unstaged changes.

Set version deliberately leaves an uncommitted bump to packages/parity/package.json in the tree — npm already has that version and the file is never committed. A dirty tree makes git pull --rebase abort, so the push never ran.

Fallout on v0.33.9: npm and the GitHub release are fine, but plugin.json stayed at 0.33.0 and the Discord step was skipped (it runs after the failed step).

Fix

• git checkout -- packages/parity/package.json before the git work — that bump is throwaway by design.
• -c rebase.autoStash=true on the pull, so a stray build artifact can't abort the rebase the same way.

Verified

Reproduced in a scratch repo, including a competing human merge landing during the publish:

• without the fix → the exact cannot pull with rebase error
• with the fix → rebases onto the other commit, pushes, plugin.json lands at the new version, and the human commit survives

Merging publishes 0.33.10 and syncs plugin.json to it in the same run.

---

Summary by cubic

Fixes the plugin version sync so git pull --rebase no longer aborts on the uncommitted packages/parity/package.json bump, which broke v0.33.9: plugin.json stayed at 0.33.0 and the Discord step was skipped. Merging publishes 0.33.10 and syncs plugin.json to it in the same run.

• Discards the throwaway package.json bump before the git work.
• Enables rebase.autoStash so stray build artifacts can't abort the rebase the same way.

^{Written for commit 2869481. Summary will update on new commits.}