title: Fix para-scheduler migration

doc:
  - audience: Runtime Dev
    description: |
      Changing the `MigrateToV1` migration in the `ParachainScheduler` pallet to be truly idempotent. It is achieved by wrapping it in a `VersionedMigration`.

migrations:
  runtime:
    - reference: ParachainScheduler
      description: Non-critical fixup for `MigrateToV1`.

crates:
  - name: polkadot-runtime-parachains