Increase required Perl version.
Increase required Perl version.

Version 5.8 might be supported too, but I do not have any such
installation to test it.

ufal/morphodita,ufal/morphodita,ufal/morphodita,ufal/morphodita,ufal/morphodita,ufal/morphodita,ufal/morphodita,ufal/morphodita