fix 1272. Fixing aiohttp version to 3.6.2

library aioresponses 0.7.0 used only by unittests is failing
with the aiohttp version 3.7.x For the moment freezing aiohttp
version

Also allows modern versions of cherrypy and jsonschema in master branch

Change-Id: I45503fd28a2f015773b1f7200d80d5ce412df567
Signed-off-by: tierno <alfonso.tiernosepulveda@telefonica.com>