Use newer flake8 to run on ubuntu-focal Zuul machines

flake8 2.5.5  fails on ubuntu-focal zuul machines running python3.8
with the following error:
AttributeError: 'FlakesChecker' object has no attribute 'CONSTANT'

The update removes the version constraint to use newer flake8.

The linters can be run in python3.
Pylint cannot be run in python3 because mysql-python is not
compatable, so a new zuul job for pylint is now added.

The flake8 errors that the newer version raises are all suppressed,
and some of them should be addressed by someone with familiarity in
this repo.

Change-Id: Ida6447728d4175173c02130cb04a6013e4f966f9
Partial-Bug: 1895054
Signed-off-by: albailey <Al.Bailey@windriver.com>

.zuul.yaml

@@ -9,10 +9,12 @@
       jobs:
         - openstack-tox-pep8
         - openstack-tox-linters
+        - ha-tox-pylint
     gate:
       jobs:
         - openstack-tox-pep8
         - openstack-tox-linters
+        - ha-tox-pylint
     post:
       jobs:
         - stx-ha-upload-git-mirror
@@ -56,6 +58,14 @@
         nfv: https://opendev.org/starlingx/nfv
         update: https://opendev.org/starlingx/update
 
+- job:
+    name: ha-tox-pylint
+    parent: tox
+    description: |
+      Run pylint test for ha in python2.7
+    nodeset: ubuntu-bionic
+    vars:
+      tox_envlist: pylint
 - job:
     name: stx-ha-upload-git-mirror
     parent: upload-git-mirror

test-requirements.txt

@@ -1,3 +1,4 @@
+hacking
 bashate >= 0.2
 PyYAML >= 3.1.0
 yamllint >= 0.5.2

tox.ini

@@ -15,6 +15,27 @@ deps = -r{toxinidir}/test-requirements.txt
 whitelist_externals = reno
 
 [testenv:linters]
+basepython = python3
+whitelist_externals = bash
+commands =
+  bash -c "find {toxinidir}          \
+         -not \( -type d -name .?\* -prune \) \
+         -type f                              \
+         -not -name \*~                       \
+         -not -name \*.md                     \
+         \(                                   \
+          -name \*.sh                         \
+          -or -not -wholename \*/devstack/files/\* \
+          -wholename \*/devstack/\*           \
+         \)                                   \
+         -print0 | xargs -r -n 1 -0 bashate -v -e E* -i E006"
+  bash -c "find {toxinidir}        \
+            \( -name middleware/io-monitor/recipes-common/io-monitor/io-monitor/io_monitor/test-tools/yaml/* -prune \) \
+            -o \( -name .tox -prune \)         \
+            -o -type f -name '*.yaml'       \
+            -print0 | xargs -0 yamllint"
+
+[testenv:pylint]
 basepython = python2.7
 deps = {[testenv]deps}
        eventlet
@@ -32,24 +53,7 @@ deps = {[testenv]deps}
        sqlalchemy-migrate
        wsme
        pylint
-whitelist_externals = bash
 commands =
-  bash -c "find {toxinidir}          \
-         -not \( -type d -name .?\* -prune \) \
-         -type f                              \
-         -not -name \*~                       \
-         -not -name \*.md                     \
-         \(                                   \
-          -name \*.sh                         \
-          -or -not -wholename \*/devstack/files/\* \
-          -wholename \*/devstack/\*           \
-         \)                                   \
-         -print0 | xargs -0 bashate -v"
-  bash -c "find {toxinidir}        \
-            \( -name middleware/io-monitor/recipes-common/io-monitor/io-monitor/io_monitor/test-tools/yaml/* -prune \) \
-            -o \( -name .tox -prune \)         \
-            -o -type f -name '*.yaml'       \
-            -print0 | xargs -0 yamllint"
   pylint --rcfile=./pylint.rc --extension-pkg-whitelist=greenlet \
          ./service-mgmt-api/sm-api/sm_api/ \
          ./service-mgmt-tools/sm-tools/sm_tools/ \
@@ -68,15 +72,24 @@ commands =
 # H404: multi line docstring should start without a leading new line
 # H405: multi line docstring summary not separated with an empty line
 # H501: Do not use locals() for string formatting
+# W are warnings
+# W504 W504 line break after binary operator
+# W605 invalid escape sequence 
 # - errors -
+# E741 ambiguous variable name
 # F811 redefinition of unused '<foo>' from line <x>
 # F821 undefined name 'e'
+# F841 local variable
+# F901 'raise NotImplemented' should be 'raise NotImplementedError'
 # - bugbear -
 # B008 Do not perform calls in argument defaults. The call is performed only once at function definition time.
+# B014 Redundant exception types
 ignore= E402,
         H102,H104,H105,H106,H306,H401,H403,H404,H405,H501,
-        F811,F821,
-        B008
+        W504,W605,
+        E741,
+        F811,F821,F841,F901,
+        B008,B014
 # Enable checks which are off by default
 # H106 Don’t put vim configuration in source files (off by default). SHOULD BE ENABLED.
 # H203 Use assertIs(Not)None to check for None (off by default).
@@ -89,9 +102,8 @@ basepython = python3
 usedevelop = False
 skip_install = True
 deps =
-    hacking
-    flake8-bugbear<=19.3.0
-    flake8 < 3.6.0
+    -r{toxinidir}/test-requirements.txt
+    flake8-bugbear
 commands =
     flake8