Update validation.js

[likemusic]

Fix to allow use decimals less then 1 in subproducts qty.

Description

There is impossible to place order from grouped product where subproducts qty less then one.

Fixed Issues (if relevant)

1. 'validate-grouped-qty' validation is meaningless #14692: 'validate-grouped-qty' validation is meaningless

Manual testing scenarios

1. Set "Qty Uses Decimals" = Yes and Minimum Qty Allowed in Shopping Cart" = 0.01 for all products on any grouped product.
2. Go to groped product page on frontend.
3. Put for all suproducts qty less than 1.

Contribution checklist

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/integration tests (if applicable)
• All automated tests passed successfully (all builds on Travis CI are green)

[VladimirZaets]

@likemusic Unfortunately, we can't accept PR from the Magento repository, please fork Magento repository and create new PR from your fork.

[likemusic]

By the way, why I can create branch in official repo? Because I become member of "Magento" organization?
I did it by accident. But perhaps it would be better not to be able to create new branches in off repository to all megento organization members?

[orlangur]

@likemusic probably because otherwise it is not possible to reopen issues / change assignee.