bump dockerfile version

Author: mroote

docker/Dockerfile

@@ -4,7 +4,7 @@ FROM frolvlad/alpine-glibc
 MAINTAINER Mitch Roote <mitch@r00t.ca>
 
 ENV FACTORIO_VERSION=latest \
- MANAGER_VERSION=0.7.3 \
+ MANAGER_VERSION=0.7.4 \
  ADMIN_PASSWORD=factorio
 
 VOLUME /opt/factorio/saves /opt/factorio/mods /opt/factorio/config /security