py: Fix useless-object-inheritance linting error

Class does not need to inherit from object anymore in Python3.

Done by:
  sed -E -i 's/^(.*)class (.+)\(object\)\:/\1class \2\:/g' \
  `find -name "*.py" -type f -xtype f`
then do manual cleanup on the rest.

BUG=b:158811392
TEST=make lint; make test

Cq-Depend: chromium:2193353
Change-Id: I1d31e49d2a2775657726a6c8f16a637083249b55
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/factory/+/2245548
Reviewed-by: Yong Hong <yhong@chromium.org>
Commit-Queue: Fei Shao <fshao@chromium.org>
Tested-by: Fei Shao <fshao@chromium.org>
Auto-Submit: Fei Shao <fshao@chromium.org>
diff --git a/py/utils/pygpt.py b/py/utils/pygpt.py
index 6e0e0de..364c666 100755
--- a/py/utils/pygpt.py
+++ b/py/utils/pygpt.py
@@ -46,7 +46,7 @@
   pass
 
 
-class StructField(object):
+class StructField:
   """Definition of a field in struct.
 
   Attributes:
@@ -145,7 +145,7 @@
   return property(_getter, _setter)
 
 
-class PartitionAttributes(object):
+class PartitionAttributes:
   """Wrapper for Partition.Attributes.
 
   This can be created using Partition.attrs, but the changed properties won't
@@ -239,7 +239,7 @@
   pass
 
 
-class GPTObject(object):
+class GPTObject:
   """A base object in GUID Partition Table.
 
   All objects (for instance, header or partition entries) must inherit this
@@ -357,7 +357,7 @@
 
     Note the meta attributes won't be cleared.
     """
-    class ZeroReader(object):
+    class ZeroReader:
       """A /dev/zero like stream."""
 
       @staticmethod
@@ -367,7 +367,7 @@
     self.Unpack(ZeroReader())
 
 
-class GPT(object):
+class GPT:
   """A GPT helper class.
 
   To load GPT from an existing disk image file, use `LoadFromFile`.
@@ -935,7 +935,7 @@
     return None
 
 
-class GPTCommands(object):
+class GPTCommands:
   """Collection of GPT sub commands for command line to use.
 
   The commands are derived from `cgpt`, but not necessary to be 100% compatible
@@ -978,7 +978,7 @@
     """Execute the sub commands by given parsed arguments."""
     return self.commands[args.command].Execute(args)
 
-  class SubCommand(object):
+  class SubCommand:
     """A base class for sub commands to derive from."""
 
     def DefineArgs(self, parser):