tox: fix pylint errors

Adapt configuration and code to pylint 2.14:

pylintrc:1 Unrecognized option found: no-space-check
[unrecognized-option]

pylintrc:1 Useless option value for '--disable', 'bad-continuation' was
removed from pylint, see pylint-dev/pylint#3571.
[useless-option-value]

pylintrc:1 Unknown option value for '--disable', expected a valid pylint
message and got 'no-self-use' [unknown-option-value]

libyang/diff.py:33 Lambda expression assigned to a variable. Define
a function using the "def" keyword instead.
[unnecessary-lambda-assignment]

libyang/keyed_list.py:118 Unnecessarily calls dunder method
__contains__. Use in keyword. [unnecessary-dunder-call]

setup.py:77 Implicit string concatenation found in call
[implicit-str-concat]

Signed-off-by: Robin Jarry <robin@jarry.cc>

Author: rjarry

libyang/diff.py

@@ -30,6 +30,7 @@ def schema_diff(
         An iterator that yield `SNodeDiff` objects.
     """
     if exclude_node_cb is None:
+        # pylint: disable=unnecessary-lambda-assignment
         exclude_node_cb = lambda n: False
 
     def flatten(node, dic):

libyang/keyed_list.py

@@ -115,7 +115,7 @@ def __str__(self):
         return str(list(self._map.values()))
 
     def count(self, element: Any):
-        if self.__contains__(element):
+        if element in self:
             return 1
         return 0