Update dependencies

docker-xmpp-notify.py

@@ -23,6 +23,7 @@ base_url = "https://hub.docker.com/v2/repositories"
 
 client = docker.from_env()
 
+
 class SendMsg(sleekxmpp.ClientXMPP):
 
     def __init__(self, jid, password, recipient, message):

requirements.txt

@@ -1,10 +1,3 @@
-certifi==2017.4.17
-chardet==3.0.4
-docker==2.3.0
-docker-pycreds==0.2.1
-idna==2.5
+docker>=2.3.0,<=2.4.2
 requests==2.18.1
-six==1.10.0
 sleekxmpp==1.3.2
-urllib3==1.21.1
-websocket-client==0.42.1