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/cloudinit/templater.py b/cloudinit/templater.py
index a00ade20..009bed32 100644
--- a/cloudinit/templater.py
+++ b/cloudinit/templater.py
@@ -36,14 +36,14 @@ from cloudinit import util
 LOG = logging.getLogger(__name__)
 TYPE_MATCHER = re.compile(r"##\s*template:(.*)", re.I)
 BASIC_MATCHER = re.compile(r'\$\{([A-Za-z0-9_.]+)\}|\$([A-Za-z0-9_.]+)')
-MISSING_JINJA_PREFIX = u'CI_MISSING_JINJA_VAR/'
+MISSING_JINJA_PREFIX = 'CI_MISSING_JINJA_VAR/'
 
 
 class UndefinedJinjaVariable(JUndefined):
     """Class used to represent any undefined jinja template variable."""
 
     def __str__(self):
-        return u'%s%s' % (MISSING_JINJA_PREFIX, self._undefined_name)
+        return '%s%s' % (MISSING_JINJA_PREFIX, self._undefined_name)
 
     def __sub__(self, other):
         other = str(other).replace(MISSING_JINJA_PREFIX, '')