我无法在 ubuntu 16.04 上从 7.2 升级到 php7.3，我运行以下命令：
sudo apt-get install python-software-properties
sudo LC_ALL=C.UTF-8 add-apt-repository ppa:ondrej/php
sudo apt-get update
sudo apt install php7.3
出现以下输出：
Building dependency tree
Reading state information... Done
Note, selecting 'php7.3-mongodb' for regex 'php7.3'
Note, selecting 'php7.3-memcached' for regex 'php7.3'
Note, selecting 'php7.3-msgpack' for regex 'php7.3'
Note, selecting 'php7.3-igbinary' for regex 'php7.3'
Note, selecting 'php7.3-uploadprogress' for regex 'php7.3'
Note, selecting 'php-uploadprogress' instead of 'php7.3-uploadprogress'
php7.3-msgpack is already the newest version (2.1.1+0.5.7-2+ubuntu16.04.1+deb.sury.org+4).
php7.3-mongodb is already the newest version (1.8.1-2+ubuntu16.04.1+deb.sury.org+4). …