Merge pull request bobrik#32 from salemove/upgrade

Upgrade to 5.5.1

Dockerfile

@@ -1,7 +1,7 @@
 FROM alpine:3.6
 
 RUN apk --no-cache add python py-setuptools py-pip gcc libffi py-cffi python-dev libffi-dev py-openssl musl-dev linux-headers openssl-dev libssl1.0 && \
-    pip install elasticsearch-curator==5.4.0 && \
+    pip install elasticsearch-curator==5.5.1 && \
     pip install boto3==1.4.8 && \
     pip install requests-aws4auth==0.9 && \
     pip install cryptography==2.1.3 && \