README: Add missing Perl dependency TimeDate for Date::Parse

.. for command genhtml.  Not to be mixed up with DateTime,
which is also needed (but already documented).

Author: hartwork

README

@@ -141,6 +141,7 @@ These perl packages include:
   - Memory::Process
   - Module::Load::Conditional
   - Scalar::Util
+  - TimeDate
   - Time::HiRes
 
 If your system is missing any of these, then you may be able to install them