Add Vietnamese as supported language

As 0 A.D. supports full unicode now and Vietnamese language coverage is
at a good level, let's include Vietnamese as supported language.

source/tools/dist/0ad.nsi

@@ -114,6 +114,7 @@
   !insertmacro MUI_LANGUAGE "TradChinese"
   !insertmacro MUI_LANGUAGE "Turkish"
   !insertmacro MUI_LANGUAGE "Ukrainian"
+  !insertmacro MUI_LANGUAGE "Vietnamese"
 
 ;--------------------------------
 ;Installer Sections

source/tools/dist/build-archives.sh

@@ -16,7 +16,7 @@ echo "Filtering languages"
 # Included languages
 # Note: Needs to be edited manually at each release.
 # Keep in sync with the installer languages in 0ad.nsi.
-LANGS="ast ca cs de el en_GB es eu fi fr gl hu id it ja ko nl pl pt_BR pt_PT ru sk sv tr uk zh zh_TW"
+LANGS="ast ca cs de el en_GB es eu fi fr gl hu id it ja ko nl pl pt_BR pt_PT ru sk sv tr uk vi zh zh_TW"
 
 # shellcheck disable=SC2086
 REGEX=$(printf "\|%s" ${LANGS} | cut -c 2-)