ci: refresh docs build dependencies

Author: ansible-documentation-bot[bot]

tests/requirements.txt

@@ -48,7 +48,7 @@ asyncio-pool==0.6.0
     # via antsibull-docs
 attrs==25.4.0
     # via aiohttp
-babel==2.17.0
+babel==2.18.0
     # via
     #   sphinx
     #   sphinx-intl