[webkit-dev] cant get libvpx repo here?

HI folks: i am compiling the latest webkit on ubuntu18.04. when i follow the manul to do the steps: ./Tools/Scripts/update-webkitgtk-libs i meet the problem of cant get the libvpx package. such as follows. this problem cant be fixed because of gov policy, you know. so is there any other way to dealt with this problem? thanks for your kindly reply. git clone https://chromium.googlesource.com/webm/libvpx libvpx Cloning into 'libvpx'... fatal: unable to access 'https://chromium.googlesource.com/webm/libvpx/': Failed to connect to chromium.googlesource.com port 443: Connection timed out