ci: remove pnpm cache (#73)

This may fail on Windows.

```
. prepare: > rsbuild-plugin-tailwindcss@0.2.4 build
. prepare: > rslib build
. prepare: node:fs:2822
. prepare:         binding.stat(base, false, undefined, true);
. prepare:                 ^
. prepare: Error: EPERM: operation not permitted, stat 'D:\.pnpm-store\v10\links\@rsbuild\core\1.7.3\91b5073407a61105bbc32aa7737ed72553d6ee03216d3b5dd3e14e0ec7a85018\node_modules\@rspack\core'
. prepare:     at Object.realpathSync (node:fs:2822:17)
. prepare:     at toRealPath (node:internal/modules/helpers:61:13)
. prepare:     at tryFile (node:internal/modules/cjs/loader:535:10)
. prepare:     at finalizeEsmResolution (node:internal/modules/cjs/loader:1404:18)
. prepare:     at resolveExports (node:internal/modules/cjs/loader:650:14)
. prepare:     at Function._findPath (node:internal/modules/cjs/loader:717:31)
. prepare:     at Function._resolveFilename (node:internal/modules/cjs/loader:1369:27)
. prepare:     at defaultResolveImpl (node:internal/modules/cjs/loader:1025:19)
. prepare:     at resolveForCJSWithHooks (node:internal/modules/cjs/loader:1030:22)
. prepare:     at Function._load (node:internal/modules/cjs/loader:1192:37) {
. prepare:   errno: -4048,
. prepare:   code: 'EPERM',
. prepare:   syscall: 'stat',
. prepare:   path: 'D:\\.pnpm-store\\v10\\links\\@rsbuild\\core\\1.7.3\\91b5073407a61105bbc32aa7737ed72553d6ee03216d3b5dd3e14e0ec7a85018\\node_modules\\@rspack\\core'
. prepare: }
. prepare: Node.js v22.22.0
. prepare: Failed
```

Author: colinaaa

.github/workflows/test.yml

@@ -34,7 +34,6 @@ jobs:
         uses: actions/setup-node@v4
         with:
           node-version: 22.22.0
-          cache: "pnpm"
 
       - name: Install Dependencies
         run: pnpm install && npx playwright install chromium