Fixed quickstart URL

Closes: https://git.ostc-eu.org/OSTC/OHOS/docs/-/issues/82


Signed-off-by: Pavel Zhukov <pavel.zhukov@huawei.com>

contributing/gitlab.rst

@@ -138,7 +138,7 @@ available in the `docs repository <https://git.ostc-eu.org/OSTC/OHOS/docs>`_.
 
 In terms of file format, the project unifies its documentation as
 ``ReStructuredText`` files. A RestructuredText primer is available as part of
-the Read The Docs `documentation <https://docutils.readthedocs.io/en/sphinx-docs/user/rst/quickstart.html>`_.
+the Sphinx `documentation <https://www.sphinx-doc.org/en/master/usage/restructuredtext/basics.html>`_.
 
 As a rule of thumb, anything that ends up compiled in the project documentation
 is to maintain the RestructuredText file format. Text files that are not meant to be compiled