Update version of postcss-load-config

[jscarle]

Describe the bug

In an issue originally identified in the TailwindCSS repository, I've been able to work through the upstream dependencies and found that vite relies on postcss-load-config to load it's configuration files.

tailwindlabs/tailwindcss#13927

I originally thought that this was an issue with postcss-load-config, however I later realised that support for .mts files has already been integrated into it. The issue is that vite is using a very old version of postcss-load-config.

postcss/postcss-load-config#265

What build tool (or framework if it abstracts the build tool) are you using?

vue 3.4.31, typescript 5.5.2, vue-tsc 2.0.24, vite 5.3.2, tailwindcss 3.4.4

Reproduction

https://github.com/jscarle/ReproTailwindCSS

Steps to reproduce

No response

System Info

System:
    OS: Windows 11 10.0.22631
    CPU: (24) x64 13th Gen Intel(R) Core(TM) i7-13700KF
    Memory: 48.57 GB / 63.84 GB
  Binaries:
    Node: 22.3.0 - C:\Program Files\nodejs\node.EXE
    npm: 10.8.1 - C:\Program Files\nodejs\npm.CMD
  Browsers:
    Edge: Chromium (123.0.2420.65)
    Internet Explorer: 11.0.22621.3527
  npmPackages:
    @vitejs/plugin-vue: ^5.0.5 => 5.0.5
    vite: ^5.3.2 => 5.3.2

Used Package Manager

npm

Logs

No response

Validations

• Follow our Code of Conduct
• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Make sure this is a Vite issue and not a framework-specific issue. For example, if it's a Vue SFC related bug, it should likely be reported to vuejs/core instead.
• Check that this is a concrete bug. For Q&A open a GitHub Discussion or join our Discord Chat Server.
• The provided reproduction is a minimal reproducible example of the bug.

[sapphi-red]

I wasn't able to reproduce. At least, I can say we cannot update postcss-load-config until v6 as it's a breaking change: #15869

[sapphi-red]

Closing as a duplicate of #15869