Add bounds to sphinx requirement

As ONAP was created before Oct 20 2020 in RTD, we
must set bounds to enforce a compatible Sphinx version
(see manual).

Issue-ID: DOC-782

Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>
Change-Id: I7afd592c5637f1d6300ae3070bcb28d191dc3895
1 file changed
tree: e13b1b42f3b7ee56cbff71c3f428ce5839e039e4
  1. docs/
  2. sandbox/
  3. .gitreview
  4. .readthedocs.yaml
  5. INFO.yaml