containers/docker: update to alpine 3.4

containers/docker/develop-alpine/Dockerfile

@@ -1,4 +1,4 @@
-FROM alpine:3.3
+FROM alpine:3.4
 
 RUN \
   apk add --update go git make gcc musl-dev         && \

containers/docker/master-alpine/Dockerfile

@@ -1,4 +1,4 @@
-FROM alpine:3.3
+FROM alpine:3.4
 
 RUN \
   apk add --update go git make gcc musl-dev         && \