ci: Update crowdin.yml to add locale disambiguation for language with variants (#308)

### What
- ci: Update crowdin.yml to add locale disambiguation for language with
variants, typically Dutch in the current translation PR

Author: teolemon

crowdin.yml

@@ -7,3 +7,16 @@ pull_request_labels:
 files:
   - source: /frontend/xliff/en.xlf
     translation: /frontend/xliff/%two_letters_code%.xlf
+    languages_mapping:
+      two_letters_code:
+        pt-PT: pt
+        pt-BR: pt_BR
+        zh-CN: zh
+        zh-HK: zh_HK
+        zh-TW: zh_TW
+        en-US: en
+        en-GB: en_GB
+        en-AU: en_AU
+        nl: nl
+        nl-BE: nl_BE
+        sr-CS: sr_CS