本方法除了在WSL上使用，同样对于完整桌面版的ubuntu也适用。
更新包
sudo apt-get update
sudo apt-get install gpg wget
获取官方的签名密钥副本
wget -O - https://apt.kitware.com/keys/kitware-archive-latest.asc 2>/dev/null | gpg --dearmor - | sudo tee /usr/share/keyrings/kitware-archive-keyring.gpg >/dev/null
添加源列表，更新
echo 'deb [signed-by=/usr/share/keyrings/kitware-archive-keyring.gpg] https://apt.kitware.com/ubuntu/ bionic main' | sudo tee /etc/apt/sources.list.d/kitware.list >/dev/null
sudo apt-get update
安装包kitware-archive-keyring，用于和官方源进行密钥更新
sudo rm /usr/share/keyrings/kitware-archive-keyring.gpg
sudo apt-get install kitware-archive-keyring
更新cmake
sudo apt-get install cmake
检查当前版本
cmake --version
如果出现：
The following packages have unmet dependencies:
cmake : Depends: libssl1.1 (>= 1.1.1) but it is not installable
E: Unable to correct problems, you have held broken packages.
则执行如下操作：
echo "deb http://security.ubuntu.com/ubuntu focal-security main" | sudo tee /etc/apt/sources.list.d/focal-security.list
sudo apt-get update
sudo apt-get install libssl1.1