Fixed nullability on asset model min qty column

[Godmartinz]

Description

Fixes the min_amt column from defaulting to 0, to being nullable.

Fixes # (issue)

Type of change

Please delete options that are not relevant.

• [ x] Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration

• Test A
• Test B

Test Configuration:

• PHP version:
• MySQL version
• Webserver version
• OS version

Checklist:

• I have read the Contributing documentation available here: https://snipe-it.readme.io/docs/contributing-overview
• I have formatted this PR according to the project guidelines: https://snipe-it.readme.io/docs/contributing-overview#pull-request-guidelines
• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[what-the-diff]

PR Summary

• Migration File Addition
  A new migration file has been added that updates a certain property, 'min_amt', of assets in the system. This file allows the attribute to have no defined value or be 'null', providing flexibility in managing such assets. If needed, this change can be undone, and the 'min_amt' property will revert to its original state with a default value of 'null'.

[marcusmoore]

Looks good besides one minor request.

[marcusmoore]

Thanks! Looks good!