yum: Use yum to check installed version of single package and updates for it.

saolasosme

Take into account the main readme for this section. README first.

$ yum list  systemd.x86_64
Loaded plugins: fastestmirror, langpacks
Loading mirror speeds from cached hostfile
 * base: centos2.zswap.net
 * extras: centos2.zswap.net
 * updates: centos2.zswap.net
Installed Packages
systemd.x86_64                                      219-62.el7_6.2                                      @updates
Available Packages
systemd.x86_64                                      219-62.el7_6.3                                      updates