MDL-44433 lang: Update the name of country code CV

ISO-3166 has updated this name to Cabo Verde:
https://www.iso.org/obp/ui/#iso:code:3166:CV

lang/en/countries.php

@@ -74,7 +74,7 @@ $string['CN'] = 'China';
 $string['CO'] = 'Colombia';
 $string['CR'] = 'Costa Rica';
 $string['CU'] = 'Cuba';
-$string['CV'] = 'Cape Verde';
+$string['CV'] = 'Cabo Verde';
 $string['CW'] = 'Curaçao';
 $string['CX'] = 'Christmas Island';
 $string['CY'] = 'Cyprus';