Remove use of anyjson module

The use of the anyjson module causes issues with Python 3.10 with
the following error:
`error in anyjson setup command: use_2to3 is invalid.`

The module itself hasn't been updated since 2012 and the source [0]
now errors with a 404, and there doesn't seem to be any real benefit
over the standard python json module.

[0] https://bitbucket.org/runeh/anyjson/

Change-Id: I00ae5e9545136c1b930f8cf4036b902a326e1c54

muranoagent/common/messaging/mqclient.py

@@ -16,8 +16,8 @@
 import random
 import ssl as ssl_module
 
-import anyjson
 import eventlet
+import json
 import kombu
 from oslo_service import sslutils
 
@@ -138,7 +138,7 @@ class MqClient(object):
         producer.publish(
             exchange=str(exchange),
             routing_key=str(key),
-            body=anyjson.dumps(message.body),
+            body=json.dumps(message.body),
             message_id=str(message.id)
         )
 

requirements.txt

@@ -6,7 +6,6 @@
 # of appearance. Changing the order has an impact on the overall integration
 # process, which may cause wedges in the gate later.
 pbr>=5.5.1 # Apache-2.0
-anyjson>=0.3.3 # BSD
 eventlet>=0.30.1 # MIT
 GitPython>=3.0.5 # BSD License (3 clause)
 kombu>=4.6.1 # BSD