upgrade to alpine linux 3.7 with the last openssh 7.5

Dockerfile

@@ -1,5 +1,5 @@
 # start with Alpine Linux
-FROM alpine:3.6
+FROM alpine:3.7
 MAINTAINER Christian Becker <mail@christianbecker.name>
 
 # system setup with "openssh-client"
@@ -8,4 +8,4 @@ RUN apk add --no-cache \
     && echo "! installation is finished !"
 
 # run openssh-client
-ENTRYPOINT ["/usr/bin/ssh", "-oCiphers=+3des-cbc", "-oHostKeyAlgorithms=+ssh-dss", "-oKexAlgorithms=+diffie-hellman-group1-sha1", "-oUserKnownHostsFile=/dev/null", "-oStrictHostKeyChecking=no", "-oLogLevel=quiet"]
+ENTRYPOINT ["/usr/bin/ssh", "-oCiphers=+3des-cbc", "-oHostKeyAlgorithms=+ssh-dss", "-oKexAlgorithms=+diffie-hellman-group1-sha1", "-oUserKnownHostsFile=/dev/null", "-oStrictHostKeyChecking=no", "-oLogLevel=error"]