refactor: run Go modernize

Signed-off-by: Deluan <deluan@navidrome.org>

plugins/manager_cache_test.go

@@ -142,7 +142,7 @@ var _ = Describe("purgeCacheBySize", func() {
 			now := time.Now()
 
 			// Create 5 files, 1MiB each (total 5MiB)
-			for i := 0; i < 5; i++ {
+			for i := range 5 {
 				path := filepath.Join(cacheDir, filepath.Join("dir", "file"+string(rune('0'+i))+".bin"))
 				createFileWithSize(path, 1*1024*1024, now.Add(-time.Duration(5-i)*time.Hour))
 			}