Bump paho-mqtt from 1.6.1 to 2.0.0 (#2288)

* Bump paho-mqtt from 1.6.1 to 2.0.0

Bumps [paho-mqtt](https://github.com/eclipse/paho.mqtt.python) from 1.6.1 to 2.0.0.
- [Release notes](https://github.com/eclipse/paho.mqtt.python/releases)
- [Changelog](https://github.com/eclipse/paho.mqtt.python/blob/master/ChangeLog.txt)
- [Commits](https://github.com/eclipse/paho.mqtt.python/compare/v1.6.1...v2.0.0)

---
updated-dependencies:
- dependency-name: paho-mqtt
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

* Update paho-mqtt==2.0.0

---------

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: JonnyWong16 <9099342+JonnyWong16@users.noreply.github.com>

[skip ci]

lib/paho/mqtt/matcher.py

@@ -1,4 +1,4 @@
-class MQTTMatcher(object):
+class MQTTMatcher:
     """Intended to manage topic filters including wildcards.
 
     Internally, MQTTMatcher use a prefix tree (trie) to store
@@ -6,7 +6,7 @@ class MQTTMatcher(object):
     method to iterate efficiently over all filters that match
     some topic name."""
 
-    class Node(object):
+    class Node:
         __slots__ = '_children', '_content'
 
         def __init__(self):
@@ -33,8 +33,8 @@ class MQTTMatcher(object):
             if node._content is None:
                 raise KeyError(key)
             return node._content
-        except KeyError:
-            raise KeyError(key)
+        except KeyError as ke:
+            raise KeyError(key) from ke
 
     def __delitem__(self, key):
         """Delete the value associated with some topic filter :key"""
@@ -46,8 +46,8 @@ class MQTTMatcher(object):
                  lst.append((parent, k, node))
             # TODO
             node._content = None
-        except KeyError:
-            raise KeyError(key)
+        except KeyError as ke:
+            raise KeyError(key) from ke
         else:  # cleanup
             for parent, k, node in reversed(lst):
                 if node._children or node._content is not None: