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).

It also applied fixes which were applied during the
previous release in all repos.

Issue-ID: DOC-782
Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>
Change-Id: I684efed16ac46552bfaa989ded2a4515ee6cc6a0
diff --git a/docs/tox.ini b/docs/tox.ini
index edac8c3..884c455 100644
--- a/docs/tox.ini
+++ b/docs/tox.ini
@@ -5,7 +5,10 @@
 
 [testenv:docs]
 basepython = python3
-deps = -r{toxinidir}/requirements-docs.txt
+deps =
+    -r{toxinidir}/requirements-docs.txt
+    -chttps://git.onap.org/doc/plain/etc/upper-constraints.os.txt
+    -chttps://git.onap.org/doc/plain/etc/upper-constraints.onap.txt
 commands =
     sphinx-build -b html -n -d {envtmpdir}/doctrees ./ {toxinidir}/_build/html
     echo "Generated docs available in {toxinidir}/_build/html"
@@ -16,7 +19,10 @@
 
 [testenv:docs-linkcheck]
 basepython = python3
-#deps = -r{toxinidir}/requirements-docs.txt
+deps =
+    -r{toxinidir}/requirements-docs.txt
+    -chttps://git.onap.org/doc/plain/etc/upper-constraints.os.txt
+    -chttps://git.onap.org/doc/plain/etc/upper-constraints.onap.txt
 commands = echo "Link Checking not enforced"
 #commands = sphinx-build -b linkcheck -d {envtmpdir}/doctrees ./ {toxinidir}/_build/linkcheck
 whitelist_externals = echo