fix: incorrect content-type of apk files (close #5385)

pkg/utils/file.go

@@ -163,8 +163,15 @@ func GetObjType(filename string, isDir bool) int {
 	return GetFileType(filename)
 }
 
+var extraMimeTypes = map[string]string{
+	".apk": "application/vnd.android.package-archive",
+}
+
 func GetMimeType(name string) string {
 	ext := path.Ext(name)
+	if m, ok := extraMimeTypes[ext]; ok {
+		return m
+	}
 	m := mime.TypeByExtension(ext)
 	if m != "" {
 		return m