方法1:
#转换格式
sudo openssl x509 -outform der -in ~/Downloads/mitmproxy-ca-cert.pem -out mitmproxy-ca.crt
sudo cp mitmproxy-ca-cert /usr/share/ca-certificates/mozilla/mitmproxy-ca.crt
sudo dpkg-reconfigure ca-certificates [选中新添加的证书点确定]
或
sudo update-ca-certificates