Remove lower-constraints job

As discussed during the upstream ironic community meeting on
Monday Dec 14 2020, the lower-constraints job is being removed.

Change-Id: Ie71603d57eef5f56f9a9fabac2a5283f472b135e

lower-constraints.txt

@@ -1,55 +0,0 @@
-alabaster==0.7.10
-appdirs==1.3.0
-Babel==2.3.4
-cliff==3.1.0
-cmd2==0.8.9
-coverage==4.0
-docutils==0.12
-dulwich==0.15.0
-extras==1.0.0
-fixtures==3.0.0
-flake8==2.5.5
-flake8-import-order==0.17.1
-future==0.18.2
-hacking==3.1.0
-imagesize==0.7.1
-iso8601==0.1.11
-Jinja2==2.10
-keystoneauth1==3.4.0
-linecache2==1.0.0
-MarkupSafe==1.1.1
-mccabe==0.2.1
-mox3==0.20.0
-openstackdocstheme==2.2.1
-os-client-config==1.28.0
-oslotest==3.2.0
-pbr==2.0.0
-pep8==1.5.7
-prettytable==0.7.2
-pycodestyle==2.6.0
-pyflakes==0.8.1
-Pygments==2.2.0
-pyparsing==2.4.7
-pyperclip==1.8.0
-python-dateutil==2.7.0
-python-mimeparse==1.6.0
-python-subunit==1.0.0
-pytz==2013.6
-PyYAML==3.13
-reno==3.1.0
-requests==2.14.2
-requestsexceptions==1.2.0
-six==1.14.0
-snowballstemmer==1.2.1
-Sphinx==2.0.0
-sphinxcontrib-apidoc==0.2.0
-sphinxcontrib-websupport==1.0.1
-stestr==2.0.0
-stevedore==1.29.0
-testrepository==0.0.20
-testscenarios==0.4
-testtools==2.2.0
-traceback2==1.4.0
-unittest2==1.1.0
-voluptuous==0.11.7
-wcwidth==0.1.9

zuul.d/project.yaml

@@ -2,7 +2,6 @@
     templates:
       - check-requirements
       - openstack-cover-jobs
-      - openstack-lower-constraints-jobs
       - openstack-python3-wallaby-jobs
       - publish-openstack-docs-pti
       - release-notes-jobs-python3