pylint: increase max attributes to 10

In three places we have more than 7 instances attributes, but less
then 10; instead of disabling the warning for all these cases,
increase the limit to a reasonable size of 10 and re-enable the
warnings in all the places.

osbuild/objectstore.py

@@ -40,7 +40,6 @@ def umount(target, lazy=True):
     subprocess.run(["umount"] + args + [target], check=True)
 
 
-# pylint: disable=too-many-instance-attributes
 class Object:
     def __init__(self, store: "ObjectStore"):
         self._init = True