style: fix section heading

Signed-off-by: gardar <gardar@users.noreply.github.com>

Author: gardar

docs/integration.rst

@@ -48,7 +48,7 @@ A minimal example workflow using GitHub Actions:
          run: yamllint .
 
 Integration with GitLab
-------------------------
+-----------------------
 
 You can use the following GitLab CI/CD stage to run yamllint and get the
 results as a `Code quality (Code Climate)