Consider file case when doing filename comparisons

internal/universal/check.go

@@ -73,7 +73,8 @@ func CheckVersionFile(w http.ResponseWriter, req *http.Request, torMgr *torrent.
 }
 
 func getContentMimeType(filePath string) string {
-	switch filepath.Ext(filePath) {
+	fileExt := strings.ToLower(filepath.Ext(filePath))
+	switch fileExt {
 	case ".mkv":
 		return "video/x-matroska"
 	case ".mp4":