update `pandoc` data dir

pandoc/filters/current_date.lua

@@ -1,12 +1,19 @@
 SCRIPT_NAME = "current_date.lua"
 os.setlocale("C")
 
+local utils = pandoc.utils
+
+LOCALEMAP = {
+  de = "de_DE.UTF-8",
+  en = "en_US.UTF-8",
+  it = "it_IT.UTF-8",
+  sl = "sl_SI.UTF-8",
+}
+
 return {
   { Meta = function(m)
-    if m.date == nil then
-      os.setlocale(os.getenv("LANG"))
-      m.date = os.date("%c")
-      return m
-    end
+    os.setlocale(LOCALEMAP[utils.stringify(m.lang)])
+    m.date = os.date("%c")
+    return m
   end }
 }