CVS domivogt: * Set release to 2.5.18.

[FVWM CVS]

CVSROOT:        /home/cvs/fvwm
Module name:    fvwm
Changes by:     domivogt        06/07/19 15:47:58

Modified files:
        .              : ChangeLog NEWS configure.ac 

Log message:
* Set release to 2.5.18.