[goal] Migrate testing to ubuntu focal

As per victoria cycle testing runtime and community goal[1]
we need to migrate upstream CI/CD to Ubuntu Focal(20.04).

Fixing:
- bug#1886298
Bump the lower constraints for required deps which added python3.8 support
in their later version.

- Move multinode jobs to focal nodeset

Story: #2007865
Task: #40227

Closes-Bug: #1886298

[1] https://governance.openstack.org/tc/goals/selected/victoria/migrate-ci-cd-jobs-to-ubuntu-focal>

Depends-On: https://review.opendev.org/#/c/752294/

Change-Id: Iec953f3294087cd0b628b701ad3d684cea61c057
(cherry picked from commit e21e5f609e)

.zuul.yaml

@@ -102,7 +102,7 @@
 - job:
     name: watcher-tempest-multinode
     parent: watcher-tempest-functional
-    nodeset: openstack-two-node-bionic
+    nodeset: openstack-two-node-focal
     roles:
       - zuul: openstack/tempest
     group-vars:

lower-constraints.txt

@@ -8,7 +8,7 @@ automaton==1.14.0
 beautifulsoup4==4.6.0
 cachetools==2.0.1
 certifi==2018.1.18
-cffi==1.11.5
+cffi==1.14.0
 chardet==3.0.4
 cliff==2.11.0
 cmd2==0.8.1
@@ -34,7 +34,7 @@ futurist==1.8.0
 gitdb2==2.0.3
 GitPython==2.1.8
 gnocchiclient==7.0.1
-greenlet==0.4.13
+greenlet==0.4.15
 idna==2.6
 imagesize==1.0.0
 iso8601==0.1.12
@@ -45,12 +45,12 @@ jsonpointer==2.0
 jsonschema==3.2.0
 keystoneauth1==3.4.0
 keystonemiddleware==4.21.0
-kombu==4.1.0
+kombu==5.0.0
 linecache2==1.0.0
 logutils==0.3.5
-lxml==4.1.1
+lxml==4.5.1
 Mako==1.0.7
-MarkupSafe==1.0
+MarkupSafe==1.1.1
 mccabe==0.2.1
 microversion_parse==0.2.1
 monotonic==1.4
@@ -58,7 +58,7 @@ msgpack==0.5.6
 munch==2.2.0
 netaddr==0.7.19
 netifaces==0.10.6
-networkx==2.2
+networkx==2.4
 openstacksdk==0.12.0
 os-api-ref===1.4.0
 os-client-config==1.29.0
@@ -70,7 +70,7 @@ oslo.cache==1.29.0
 oslo.concurrency==3.26.0
 oslo.config==5.2.0
 oslo.context==2.21.0
-oslo.db==4.35.0
+oslo.db==4.44.0
 oslo.i18n==3.20.0
 oslo.log==3.37.0
 oslo.messaging==8.1.2
@@ -113,7 +113,7 @@ python-novaclient==14.1.0
 python-openstackclient==3.14.0
 python-subunit==1.2.0
 pytz==2018.3
-PyYAML==3.12
+PyYAML==3.13
 repoze.lru==0.7
 requests==2.18.4
 requestsexceptions==1.4.0
@@ -130,9 +130,9 @@ sqlparse==0.2.4
 statsd==3.2.2
 stestr==2.0.0
 stevedore==1.28.0
-taskflow==3.7.1
+taskflow==3.8.0
 Tempita==0.5.2
-tenacity==4.9.0
+tenacity==4.12.0
 testresources==2.0.1
 testscenarios==0.5.0
 testtools==2.3.0

requirements.txt

@@ -7,14 +7,14 @@ jsonpatch>=1.21 # BSD
 keystoneauth1>=3.4.0 # Apache-2.0
 jsonschema>=3.2.0 # MIT
 keystonemiddleware>=4.21.0 # Apache-2.0
-lxml>=4.1.1 # BSD
+lxml>=4.5.1 # BSD
 croniter>=0.3.20 # MIT License
 os-resource-classes>=0.4.0
 oslo.concurrency>=3.26.0 # Apache-2.0
 oslo.cache>=1.29.0 # Apache-2.0
 oslo.config>=5.2.0 # Apache-2.0
 oslo.context>=2.21.0 # Apache-2.0
-oslo.db>=4.35.0 # Apache-2.0
+oslo.db>=4.44.0 # Apache-2.0
 oslo.i18n>=3.20.0 # Apache-2.0
 oslo.log>=3.37.0 # Apache-2.0
 oslo.messaging>=8.1.2 # Apache-2.0
@@ -41,9 +41,9 @@ python-openstackclient>=3.14.0 # Apache-2.0
 python-ironicclient>=2.5.0 # Apache-2.0
 SQLAlchemy>=1.2.5 # MIT
 stevedore>=1.28.0 # Apache-2.0
-taskflow>=3.7.1 # Apache-2.0
+taskflow>=3.8.0 # Apache-2.0
 WebOb>=1.8.5 # MIT
 WSME>=0.9.2 # MIT
-networkx>=2.2 # BSD
+networkx>=2.4 # BSD
 microversion_parse>=0.2.1 # Apache-2.0
 futurist>=1.8.0 # Apache-2.0