Merge pull request #2650 from reframe-hpc/dependabot/pip/docs/sphinx-5.3.0

Bump sphinx from 5.2.3 to 5.3.0 in /docs

Author: vkarak

docs/requirements.txt

@@ -2,5 +2,5 @@ archspec==0.1.4
 docutils==0.17.1 # https://github.com/sphinx-doc/sphinx/issues/9001
 jsonschema==3.2.0
 semver==2.13.0
-Sphinx==5.2.3
+Sphinx==5.3.0
 sphinx-rtd-theme==1.0.0