tox: bump the pinned flake8 and pylint version (#1029)

tox: bump the pinned flake8 and pylint version

* pylint: fix W1406 (redundant-u-string-prefix)

The u prefix for strings is no longer necessary in Python >=3.0.

* pylint: disable W1514 (unspecified-encoding)
    
From https://www.python.org/dev/peps/pep-0597/ (Python 3.10):
    
The new warning stems form https://www.python.org/dev/peps/pep-0597,
which says:
    
  Developers using macOS or Linux may forget that the default encoding
  is not always UTF-8. [...] Even Python experts may assume that the
  default encoding is UTF-8. This creates bugs that only happen on Windows.
    
The warning could be fixed by always specifying encoding='utf-8',
however we should be careful to not break environments which are not
utf-8 (or explicitly state that only utf-8 is supported). Let's silence
the warning for now.

* _quick_read_instance_id: cover the case where load_yaml() returns None

Spotted by pylint:
 - E1135 (unsupported-membership-test)
 - E1136 (unsubscriptable-object)

LP: #1944414

1 files changed, 2 insertions, 2 deletions

diff --git a/tox.ini b/tox.ini
index aad286ff..45ccadce 100644
--- a/tox.ini
+++ b/tox.ini
@@ -12,7 +12,7 @@ passenv=
 [testenv:flake8]
 basepython = python3
 deps =
-    flake8==3.8.2
+    flake8==3.9.2
 commands = {envpython} -m flake8 {posargs:cloudinit/ tests/ tools/ setup.py}
 
 # https://github.com/gabrielfalcao/HTTPretty/issues/223
@@ -23,7 +23,7 @@ setenv =
 basepython = python3
 deps =
     # requirements
-    pylint==2.9.3
+    pylint==2.11.1
     # test-requirements because unit tests are now present in cloudinit tree
     -r{toxinidir}/test-requirements.txt
     -r{toxinidir}/integration-requirements.txt