Deny the use of libjuju 2.9.46

The python-libjuju 2.9.46 release introduced the use of the walrus
operator which is incompatible with python 3.6, more details at
juju/python-libjuju#993

Author: freyes

requirements.txt

@@ -1,7 +1,8 @@
 pyparsing<3.0.0  # pin for aodhclient which is held for py35
 aiounittest
 async_generator
-juju<3.0
+# 2.9.46.0 - https://github.com/juju/python-libjuju/pull/993
+juju<3.0,!=2.9.46.0
 kubernetes<18.0.0; python_version < '3.6' # pined, as juju uses kubernetes
 juju_wait
 PyYAML>=3.0

setup.py

@@ -35,7 +35,8 @@
 
     'hvac<0.7.0',
     'jinja2',
-    'juju<3.0',
+    # 2.9.46.0 - https://github.com/juju/python-libjuju/pull/993
+    'juju<3.0,!=2.9.46',
     'juju-wait',
     'PyYAML',
     'tenacity',