Remove lower-constraints.txt

Per [1] lower-constraints aren't necessary any more, let's remove it.

[1] https://governance.openstack.org/tc/resolutions/20220414-drop-lower-constraints.html

Change-Id: I2688313c62c5fc3ceac1631c7aae3a7f5bb3ef7a

.zuul.d/project.yaml

@@ -2,7 +2,6 @@
     templates:
       - openstack-cover-jobs
       - check-requirements
-      - openstack-lower-constraints-jobs
       - release-notes-jobs-python3
       # NOTE(ianw): 2020-05-29 jobs are unstable; see
       # https://bugs.launchpad.net/tripleo/+bug/1879766

lower-constraints.txt

@@ -1,47 +0,0 @@
-alabaster==0.7.10
-appdirs==1.3.0
-astroid==1.6.2
-coverage==4.0
-decorator==4.3.0
-docutils==0.11
-dulwich==0.15.0
-extras==1.0.0
-fixtures==3.0.0
-flake8==3.8.4
-hacking==0.10.0
-imagesize==0.7.1
-iso8601==0.1.11
-isort==4.3.4
-Jinja2==2.10
-jsonschema==3.0.2
-keystoneauth1==3.4.0
-lazy-object-proxy==1.3.1
-linecache2==1.0.0
-MarkupSafe==1.0
-mock==2.0.0
-mox3==0.20.0
-networkx==2.3.0
-openstackdocstheme==1.18.1
-os-client-config==1.28.0
-oslotest==3.2.0
-pbr==2.0.0
-pep8==1.5.7
-pyflakes==2.2.0
-Pygments==2.2.0
-pylint==1.7.1
-python-mimeparse==1.6.0
-python-subunit==1.0.0
-pytz==2013.6
-PyYAML==3.12
-reno==2.5.0
-requests==2.14.2
-requestsexceptions==1.2.0
-snowballstemmer==1.2.1
-Sphinx==1.6.2
-sphinxcontrib-websupport==1.0.1
-stevedore==1.20.0
-stestr==2.0.0
-testtools==2.2.0
-traceback2==1.4.0
-unittest2==1.1.0
-wrapt==1.7.0

tox.ini

@@ -60,9 +60,3 @@ commands = sphinx-build -a -W -E -d releasenotes/build/doctrees -b html releasen
 [flake8]
 ignore = E125,E126,E127,H202,H803,W503,W504
 exclude =  .venv,.git,.tox,dist,doc/build,doc/source,*lib/python*,*egg,build,conf.py
-
-[testenv:lower-constraints]
-deps =
-  -c{toxinidir}/lower-constraints.txt
-  -r{toxinidir}/test-requirements.txt
-  -r{toxinidir}/requirements.txt