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, 5 insertions, 5 deletions

diff --git a/cloudinit/reporting/handlers.py b/cloudinit/reporting/handlers.py
index 0a8c7af3..e32739ef 100755
--- a/cloudinit/reporting/handlers.py
+++ b/cloudinit/reporting/handlers.py
@@ -137,8 +137,8 @@ class HyperVKvpReportingHandler(ReportingHandler):
         self._event_types = event_types
         self.q = queue.Queue()
         self.incarnation_no = self._get_incarnation_no()
-        self.event_key_prefix = u"{0}|{1}".format(self.EVENT_PREFIX,
-                                                  self.incarnation_no)
+        self.event_key_prefix = "{0}|{1}".format(self.EVENT_PREFIX,
+                                                 self.incarnation_no)
         self.publish_thread = threading.Thread(
             target=self._publish_event_routine
         )
@@ -200,9 +200,9 @@ class HyperVKvpReportingHandler(ReportingHandler):
         CLOUD_INIT|<incarnation number>|<event_type>|<event_name>|<uuid>
         [|subevent_index]
         """
-        return u"{0}|{1}|{2}|{3}".format(self.event_key_prefix,
-                                         event.event_type, event.name,
-                                         uuid.uuid4())
+        return "{0}|{1}|{2}|{3}".format(self.event_key_prefix,
+                                        event.event_type, event.name,
+                                        uuid.uuid4())
 
     def _encode_kvp_item(self, key, value):
         data = struct.pack(