Tempative minor fix for Pontoon

This CL adds a reference for the lit localization files in the
i18n-config.toml file to try to make those files sync with Pontoon.

Bug: twpowertools:157
Change-Id: Ib4643a66bbda15137d269c6a17f46f71598f4205
diff --git a/i18n-config.toml b/i18n-config.toml
index dd55467..fa1abcc 100644
--- a/i18n-config.toml
+++ b/i18n-config.toml
@@ -32,4 +32,5 @@
   l10n = "cws/{android_locale}/listing-description.lang"
 
 [[paths]]
+  reference = "src/lit-locales/source/es.xlf"
   l10n = "src/lit-locales/source/{android_locale}.xlf"