Add Louisiana Creole (lou) (#378)

It has been on translatewiki.net for a while
so it should be here, too.

data/langdb.yaml

@@ -448,6 +448,7 @@ languages:
   lmo: [Latn, [EU], lombard]
   ln: [Latn, [AF], lingála]
   lo: [Laoo, [AS], ລາວ]
+  lou: [Latn, [AM], Kouri-Vini]
   loz: [Latn, [AF], Silozi]
   lrc: [Arab, [AS, ME], لۊری شومالی]
   lt: [Latn, [EU], lietuvių]

data/language-data.json

@@ -2783,6 +2783,13 @@
             ],
             "ລາວ"
         ],
+        "lou": [
+            "Latn",
+            [
+                "AM"
+            ],
+            "Kouri-Vini"
+        ],
         "loz": [
             "Latn",
             [