Update readability-lxml to version 0.9.0 for Python 3.9 compatibility

Author: ple76

setup.py

@@ -129,7 +129,7 @@
     "raven==6.10.0",
     "rax-default-network-flags-python-novaclient-ext==0.4.0",
     "rax-scheduled-images-python-novaclient-ext==0.3.1",
-    "readability-lxml==0.8.1",
+    "readability-lxml==0.9.0",  # Updated for Python 3.9 compatibility
     "redis==3.5.3",
     "rednose==1.3.0",
     "requests==2.31.0",