我正试图让Flutter Doctor修复一些问题，但会遇到以下问题。
$flutter doctor
Doctor summary (to see all details, run flutter doctor -v):
[✓] Flutter (Channel stable, v1.12.13+hotfix.8, on Mac OS X 10.14.6 18G87, locale en-DE)
Checking Android licenses is taking an unexpectedly long time...⣻
我尝试安装证书，但是使用时
$flutter doctor --android-licenses
我陷入困境
[========= ] 25% Fetch remote repository...