Cap jsonschema 3.2.0 as the minimal version

Previous versions of jsonschema (<3.2.0) doesn't support python 3.8 [1].
Python 3.8 is part of the victoria supported runtimes [2] so we now force
to use jsonschema version 3.2.0 to avoid issues, remove ambiguity and ensure
that everything works with python 3 in general.

[1] python-jsonschema/jsonschema#627
[2] https://governance.openstack.org/tc/reference/runtimes/victoria.html#python-runtimes-for-victoria

Change-Id: I65b1fcff16f7633325a0f42c4ac9ef442f1b352b

Author: 4383

lower-constraints.txt

@@ -8,7 +8,7 @@ dogpile.cache==0.6.2
 eventlet==0.20.0
 fixtures==3.0.0
 Jinja2==2.10
-jsonschema==2.6.0
+jsonschema==3.2.0
 keystonemiddleware==4.18.0
 kombu==4.6.1
 mistral-lib==1.4.0

requirements.txt

@@ -9,7 +9,7 @@ cachetools>=2.0.0 # MIT License
 dogpile.cache>=0.6.2 # BSD
 eventlet!=0.20.1,!=0.21.0,!=0.23.0,!=0.25.0,>=0.20.0 # MIT
 Jinja2>=2.10 # BSD License (3 clause)
-jsonschema>=2.6.0 # MIT
+jsonschema>=3.2.0 # MIT
 keystonemiddleware>=4.18.0 # Apache-2.0
 kombu!=4.0.2,>=4.6.1 # BSD
 mistral-lib>=1.4.0 # Apache-2.0