Fix depreciated calls of fetch_env!/2 and get_env/2

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

lib/mobilizon/cldr.ex

@@ -4,10 +4,10 @@ defmodule Mobilizon.Cldr do
   """
 
   use Cldr,
-    locales: Application.get_env(:mobilizon, :cldr)[:locales],
+    locales: locales(),
     add_fallback_locales: true,
     gettext:
-      if(Application.fetch_env!(:mobilizon, :env) == :prod,
+      if(Application.compile_env(:mobilizon, :env) == :prod,
         do: Mobilizon.Web.Gettext,
         else: nil
       ),
@@ -27,4 +27,8 @@ defmodule Mobilizon.Cldr do
       default
     end
   end
+
+  defp locales do
+    Application.get_env(:mobilizon, :cldr)[:locales]
+  end
 end