doc: lower the sections of publish related jobs

README.md

@@ -229,7 +229,7 @@ directory _(relative to project root dir)_.
 
 ### Publish jobs
 
-### `py-release` job
+#### `py-release` job
 
 This job is **disabled by default** and performs an automatic tagging of your Python code.
 
@@ -249,7 +249,7 @@ It is bound to the `publish` stage, applies only on master branch and uses the f
 | `RELEASE_USERNAME`     | Username credential for git push                                        | _none_ (disabled) |
 | `RELEASE_ACCESS_TOKEN` | Password credential for git push                                        | _none_            |
 
-### `py-publish` job
+#### `py-publish` job
 
 This job is **disabled by default** and performs a packaging and publication of your Python code.
 
@@ -267,7 +267,7 @@ More info:
 
 If you want to automatically create tag and publish your Python package, please have a look [here](#release-python)
 
-### `py-docs` job
+#### `py-docs` job
 
 This job is **disabled by default** and performs documentation generation of your Python code using [Sphinx](http://www.sphinx-doc.org/en/master/). Documentation will be available through a GitLab artifact.