Don't start CI builds for the changes to message catalogs only

We currently don't use these files in the existing builds.

It might be a good idea to add another GitHub Action workflow checking
the message catalogs compilation that would be executed _only_ for the
changes to them, but this can/will be done later.

.github/workflows/ci.yml

@@ -14,6 +14,7 @@ on:
       - 'interface/**'
       - 'include/msvc/**'
       - 'include/wx/msw/**'
+      - 'locale/**'
       - 'src/wx/msw/**'
       - '*.md'
       - '*.yml'
@@ -30,6 +31,7 @@ on:
       - 'interface/**'
       - 'include/msvc/**'
       - 'include/wx/msw/**'
+      - 'locale/**'
       - 'src/wx/msw/**'
       - '*.md'
       - '*.yml'