我正在尝试通过运行以下命令来安装旧版本的 mysql [5.6.45]：
apt-get install mysql-server-5.6
但我收到了这个错误：
The following packages have unmet dependencies:
mysql-server-5.6 : Depends: initscripts but it is not installable
Depends: sysv-rc (>= 2.88dsf-24) but it is not installable
or
file-rc (>= 0.8.16) but it is not installable
Recommends: libhtml-template-perl but it is not going to be
installed
E: Unable to correct problems, you have held broken packages.
如果我运行：
apt-get install initscripts
我收到此消息：
Package initscripts is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source
However the following packages replace it:
bootlogd util-linux sysvinit-utils
E: Package 'initscripts' has no installation candidate
我应该怎么做才能安装 mysql 5.6（最好是 5.6.45）？
PS：我使用的是 Ubuntu 18.04