kdenlive ppa 新增

For Ubuntu >= 15.04 and other *buntu based distros like LinuxMint you can download latest Kdenlive from our official PPA’s:

sudo add-apt-repository ppa:kdenlive/kdenlive-stable
sudo apt-get update
sudo apt-get install kdenlive

Note: you can easily remove our PPA and revert back to official distro package using:
sudo ppa-purge ppa:kdenlive/kdenlive-stable
參考：https://kdenlive.org/download/