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: Ie5e6a655b103dd7edb447f56bff8da870193deba

lower-constraints.txt

@@ -1,63 +0,0 @@
-appdirs==1.4.3
-asn1crypto==0.24.0
-Babel==2.5.3
-certifi==2018.1.18
-cffi==1.13.0
-chardet==3.0.4
-cliff==3.1.0
-cmd2==0.8.9
-coverage==4.0
-cryptography==2.2.1
-debtcollector==1.19.0
-decorator==4.4.2
-dogpile.cache==0.6.5
-extras==1.0.0
-fixtures==3.0.0
-future==0.18.2
-idna==2.6
-iso8601==0.1.12
-jmespath==0.10.0
-jsonpatch==1.28
-jsonpointer==2.0
-keystoneauth1==3.18.0
-linecache2==1.0.0
-monotonic==1.4
-msgpack==0.5.6
-munch==2.5.0
-netaddr==0.7.19
-netifaces==0.10.6
-openstacksdk==0.37.0
-os-service-types==1.7.0
-oslo.config==5.2.0
-oslo.context==2.20.0
-oslo.i18n==3.20.0
-oslo.log==3.36.0
-oslo.serialization==2.25.0
-oslo.utils==3.36.0
-passlib==1.7.2
-pbr==2.0.0
-prettytable==0.7.2
-pycparser==2.18
-pyinotify==0.9.6
-pyOpenSSL==18.0.0
-pyparsing==2.2.0
-pyperclip==1.8.0
-python-dateutil==2.7.0
-python-mimeparse==1.6.0
-python-subunit==1.2.0
-pytz==2018.3
-PyYAML==3.12
-requests==2.18.4
-requestsexceptions==1.4.0
-rfc3986==1.1.0
-setuptools==39.0.1
-six==1.15.0
-stestr==2.0.0
-stevedore==1.28.0
-testtools==2.2.0
-traceback2==1.4.0
-unittest2==1.1.0
-urllib3==1.22
-voluptuous==0.11.7
-wcwidth==0.1.9
-wrapt==1.10.11

zuul.d/project.yaml

@@ -1,7 +1,6 @@
 - project:
     templates:
       - openstack-python3-wallaby-jobs
-      - openstack-lower-constraints-jobs
       - check-requirements
       - publish-openstack-docs-pti
       - release-notes-jobs-python3