Upgrade system needs finishing!

[cgcmart]

What version of OpenCart are you reporting this for?
Master branch
Describe the bug
A clear and concise description of what the bug is
What section does it affect?

Error: Could not load model Opencart\Application\Model\Upgrade\Upgrade1000! in /home/.../www/system/engine/loader.php on line 111
PHP Fatal error: Uncaught Error: Call to a member function upgrade() on string in /home/.../www/install/controller/upgrade/upgrade.php:56

To Reproduce
Steps to reproduce the behavior:

1. Go to '.../install/index.php?route=upgrade/upgrade'
2. Click on 'Continue'
3. Scroll down to '....'
4. See error

Expected behavior
A clear and concise description of what you expected to happen.

Screenshots / Screen recordings
If applicable, add screenshots or recordings to help explain your problem. Please keep these short and if you can, edit them to point out when/where the problem is.
https://www.useloom.com/ is perfect for screen recording with Chrome or with their desktop app

Server / Test environment (please complete the following information):

• Local development? Deployed to a web server?
• Operating system
• PHP version
• Apache version
• Browser(s) tested with [e.g. chrome, safari - if applicable]
• Version [e.g. 22]

Additional context
Add any other context about the problem here.