Fix CI docs build on minor release branches

.gitlab-ci.yml

@@ -188,4 +188,4 @@ pages:
     paths:
     - public
   rules:
-    - if: '$CI_COMMIT_TAG =~ /v[0-9]+[.][0-9]+[.][0-9]+.*/ || $CI_COMMIT_BRANCH == "master"'
+    - if: '$CI_COMMIT_BRANCH =~ /v[0-9]+[.][0-9]+[.]x$/ || $CI_COMMIT_BRANCH == "master"'