backup_migrate_update_5001 is never executed due to CORE_MINIMUM_SCHEMA_VERSION

Created MR, update hook is now successfully run on existing Drupal site.

It should be named backup_migrate_update_50001, indicating its connection to v5, rather than 8001.

This updates it to 50001.

@DamienMcKenna maybe it would be better to rename it to 9501 or 10501? That would be more according to the documentation guidelines:

• 1 or 2 digits for Drupal core compatibility (Drupal 8, 9, 10, etc.). This convention must be followed.
• 1 digit for your module's major release version; for example, for 8.x-1.* use 1, for 8.x-2.* use 2, for Core 8.0.x use 0, and for Core 8.1.x use 1. This convention is optional but suggested for clarity.
• 2 digits for sequential counting, starting with 01. Note that the x000 number can never be used: the lowest update number that will be recognized and run for major version x is x001.

Committed. Thank you for spotting this!

Automatically closed - issue fixed for 2 weeks with no activity.