Remove Python 2.7 test triggers from Zuul

This commit removes Python 2.7 jobs from Zuul, since it will no longer
be executed as part of the check and gate steps for nginx ingress
controller repository.

Additionally, this commit updates the package PyYaml to 5.3.1 version
to support oslo-policy 3.5.0 dependency on PyYAML>=5.1. Also, fixes
some lint errors.

Test Plan:
PASS: Verify Zuul check execution and observe the Workflow +1 at the
      end of the proccess.

Story: 2010531
Task: 47566

Signed-off-by: Manoel Benedito Neto <manoel.beneditoneto@windriver.com>
Change-Id: Icefa2545c325872129088ff51ddc193bb1f9e135

.zuul.yaml

@@ -3,7 +3,6 @@
     check:
       jobs:
         - openstack-tox-linters
-        - k8sapp-nginx-ingress-controller-tox-py27
         - k8sapp-nginx-ingress-controller-tox-py39
         - k8sapp-nginx-ingress-controller-tox-flake8
         - k8sapp-nginx-ingress-controller-tox-pylint
@@ -11,7 +10,6 @@
     gate:
       jobs:
         - openstack-tox-linters
-        - k8sapp-nginx-ingress-controller-tox-py27
         - k8sapp-nginx-ingress-controller-tox-py39
         - k8sapp-nginx-ingress-controller-tox-flake8
         - k8sapp-nginx-ingress-controller-tox-pylint
@@ -20,23 +18,6 @@
       jobs:
         - stx-nginx-ingress-controller-armada-app-upload-git-mirror
 
-- job:
-    name: k8sapp-nginx-ingress-controller-tox-py27
-    parent: tox
-    description: |
-      Run py27 test for k8sapp-nginx-ingress-controller
-    nodeset: ubuntu-xenial
-    required-projects:
-      - starlingx/config
-      - starlingx/fault
-      - starlingx/update
-      - starlingx/utilities
-    files:
-      - python3-k8sapp-nginx-ingress-controller/*
-    vars:
-      tox_envlist: py27
-      tox_extra_args: -c python3-k8sapp-nginx-ingress-controller/k8sapp_nginx_ingress_controller/tox.ini
-
 - job:
     name: k8sapp-nginx-ingress-controller-tox-py39
     parent: tox-py39
@@ -72,7 +53,7 @@
     parent: tox
     description: |
       Run pylint test for k8sapp-nginx-ingress-controller
-    nodeset: ubuntu-xenial
+    nodeset: ubuntu-focal
     required-projects:
       - starlingx/config
       - starlingx/fault

python3-k8sapp-nginx-ingress-controller/k8sapp_nginx_ingress_controller/k8sapp_nginx_ingress_controller/operator/__init__.py

@@ -13,7 +13,7 @@ class quoted_str(str):
 
 # force strings to be single-quoted to avoid interpretation as numeric values
 def quoted_presenter(dumper, data):
-    return dumper.represent_scalar(u'tag:yaml.org,2002:str', data, style="'")
+    return dumper.represent_scalar('tag:yaml.org,2002:str', data, style="'")
 
 
 yaml.add_representer(quoted_str, quoted_presenter)

python3-k8sapp-nginx-ingress-controller/k8sapp_nginx_ingress_controller/k8sapp_nginx_ingress_controller/operator/manifest_nginx.py

@@ -34,4 +34,3 @@ class IngressNginxArmadaManifestOperator(base.ArmadaManifestOperator):
         :param dbapi: DB api object
         :param mode: mode to control how to apply the application manifest
         """
-        pass

python3-k8sapp-nginx-ingress-controller/k8sapp_nginx_ingress_controller/requirements.txt

@@ -1,3 +1,2 @@
 pbr>=2.0.0
-PyYAML==5.3.1;python_version>="3.9"
-PyYAML==3.1.3;python_version<"3.9"
+PyYAML==5.3.1

python3-k8sapp-nginx-ingress-controller/k8sapp_nginx_ingress_controller/setup.cfg

@@ -14,8 +14,6 @@ classifier =
     License :: OSI Approved :: Apache Software License
     Operating System :: POSIX :: Linux
     Programming Language :: Python
-    Programming Language :: Python :: 2
-    Programming Language :: Python :: 2.7
     Programming Language :: Python :: 3
     Programming Language :: Python :: 3.4
     Programming Language :: Python :: 3.5

python3-k8sapp-nginx-ingress-controller/k8sapp_nginx_ingress_controller/tox.ini

@@ -1,5 +1,5 @@
 [tox]
-envlist = flake8,py27,py36,py39,pylint,bandit
+envlist = flake8,py36,py39,pylint,bandit
 minversion = 1.6
 # disable source dist generation because Zuul fails on setting up
 # pbr randomly in the sdist step.
@@ -24,7 +24,7 @@ allowlist_externals = bash
 
 install_command = pip install \
     -v -v -v \
-    -c{env:UPPER_CONSTRAINTS_FILE:https://opendev.org/openstack/requirements/raw/branch/stable/stein/upper-constraints.txt} \
+    -c{env:UPPER_CONSTRAINTS_FILE:https://opendev.org/starlingx/root/raw/branch/master/build-tools/requirements/debian/upper-constraints.txt} \
     {opts} {packages}
 
 # Note the hash seed is set to 0 until can be tested with a
@@ -77,13 +77,6 @@ deps = -r{toxinidir}/test-requirements.txt
 commands =
   flake8 {posargs} .
 
-[testenv:py27]
-basepython = python2.7
-commands =
-  {[testenv]commands}
-  stestr run {posargs}
-  stestr slowest
-
 [testenv:py36]
 basepython = python3.6
 commands =
@@ -123,7 +116,7 @@ deps = -r{toxinidir}/test-requirements.txt
 commands = bandit --ini tox.ini -n 5 -r k8sapp_nginx_ingress_controller
 
 [testenv:pylint]
-basepython = python2.7
+basepython = python3
 sitepackages = False
 
 deps = {[testenv]centos_deps}
@@ -132,7 +125,7 @@ commands =
      pylint {posargs} k8sapp_nginx_ingress_controller --rcfile=./pylint.rc
 
 [testenv:cover]
-basepython = python2.7
+basepython = python3
 deps = {[testenv]centos_deps}
 setenv = {[testenv]setenv}
          PYTHON=coverage run --parallel-mode