chore: path relative should be case

Author: sonofmagic

packages/unplugin-tailwindcss-mangle/test/path.test.ts

@@ -4,6 +4,6 @@ describe('path', () => {
   it('should be', () => {
     const context = 'C:\\github-workspace\\tailwindcss-mangle\\apps\\next-app\\.next\\'
     const target = path.resolve('C:\\github-workspace\\tailwindcss-mangle\\apps\\next-app\\.next\\server\\chunks', '../pages/_app.js')
-    expect(path.relative(context, target)).toBe('')
+    expect(path.relative(context, target)).toBe('server\\pages\\_app.js')
   })
 })