magento2.3 – Invoice QTY bug Magento 2.3

We have came across a bug in Magento regarding Quantity is not accepting 0.5 on invoic and it is apparently a common issue.

I have found the solution on git hub but I just need some help regarding this.

I know you should not edit any file in vendor/… but try to overwrite it by put the files under app/… as you can see in the github solution.

My question is, when I have copied all of the files and put them under app/…. as referred in github, do i need to create a registration.php to make it work? and do i need anything else?

Any help is appreciated .