fix: customConfig.resolve two files with the same modification time

[hartbit]

Resolve issues with loading different config files with the same modification time

Description

We were experiencing issue #241 and tracked it down to the customConfig.resolve function erroneously using the cached config because the two tailwind config files in our project share the same modification time (after a git pull).

Fixes #241

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

We tested this fix by adding unit tests for customConfig.resolve.

Test Configuration:

• OS + version: macOS Sonoma
• NPM version: 10.8.2
• Node version: 20.18.0

Checklist:

• 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
• Any dependent changes have been merged and published in downstream modules
• I have checked my code and corrected any misspellings

[sloanesturz]

Hi @francoismassart -- could you take a look and potentially merge this in? I'm experiencing this bug on my end as well.

Thanks! (And thank you @hartbit for the fix!)