Update Configuration.h

Marlin/Configuration.h

 // @section lcd
 
 // Define your display language below. Replace (en) with your language code and uncomment.
-// en, pl, fr, de, es, ru, bg, it, pt, pt-br, fi, an, nl, ca, eu, kana, kana_utf8, cn, test
+// en, pl, fr, de, es, ru, bg, it, pt, pt-br, fi, an, nl, ca, eu, kana, kana_utf8, cn, cz, test
 // See also language.h
 #define LANGUAGE_INCLUDE GENERATE_LANGUAGE_INCLUDE(en)