Fix issue with Portuguese language in the CWS

In the Chrome Web Store, the Portuguese language wasn't listed as
supported by the extension, and this prevented us from filling in the
translated listing description.

This CL fixes the issue by creating 2 Portuguese folders at build time
(pt_BR and pt_PT) with the same contents, instead of using the pt
language code which isn't officially supported by the CWS.

Change-Id: Ibf0f7893d4cd8a3df4ba1b6b3df2bec7be118ea6
diff --git a/webpack.config.js b/webpack.config.js
index 7807749..c8c3fcc 100644
--- a/webpack.config.js
+++ b/webpack.config.js
@@ -10,7 +10,11 @@
 const localeOverrides = [
     pontoonLocale: 'pt-rBR',
-    webExtLocale: 'pt',  // This way it targets both 'pt_BR' and 'pt_PT'
+    webExtLocale: 'pt_BR',
+  },
+  {
+    pontoonLocale: 'pt-rBR',
+    webExtLocale: 'pt_PT',