[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).

Bump the lower constraints for required deps which added
python3.8 support in their later version.
Story: #2007865
Task: #40218

If we move horizon jobs to focal then  senlin-dashboard 'nodejs-test'
job fails. This patch adds libfontconfig1 in bindep.txt as phantomjs
requires libfontconfig[2] to fix failed nodejs job.

Closes-Bug: #1886298

[1] https://governance.openstack.org/tc/goals/selected/victoria/migrate-ci-cd-jobs-to-ubuntu-focal
[2] https://www.npmjs.com/package/phantomjs-prebuilt#linux-note

Change-Id: If95f8005d31ce340f2dec1c3fe0d732ecb5a06ca
Co-Author: Ghanshyam Mann <gmann@ghanshyammann.com>

bindep.txt

@@ -0,0 +1,4 @@
+# This is a cross-platform list tracking distribution packages needed for install and tests;
+# see https://docs.openstack.org/infra/bindep/ for additional information.
+
+libfontconfig1 [nodejs platform:dpkg]

lower-constraints.txt

@@ -3,7 +3,7 @@ appdirs==1.4.3
 asn1crypto==0.24.0
 Babel==2.5.3
 certifi==2018.1.18
-cffi==1.11.5
+cffi==1.14
 chardet==3.0.4
 cliff==2.11.0
 cmd2==0.8.1