Use LABEL instead of MAINTAINER

The MAINTAINER instruction is deprecated since Docker 1.13.0 and should not be used anymore.

Instead the more flexible LABEL instruction can be used

Documentation:

https://docs.docker.com/engine/deprecated/#maintainer-in-dockerfile

https://docs.docker.com/engine/reference/builder/#maintainer-deprecated

Dockerfile.local

@@ -1,6 +1,6 @@
 FROM ubuntu:16.04
 
-MAINTAINER mbredel "https://github.com/mbredel"
+LABEL maintainer="mbredel https://github.com/mbredel"
 
 # Install packages for building the LaTeX template.
 RUN apt-get -qq update && apt-get install -y --no-install-recommends \

Dockerfile.travis

@@ -1,6 +1,6 @@
 FROM ubuntu:16.04
 
-MAINTAINER mbredel "https://github.com/mbredel"
+LABEL maintainer="mbredel https://github.com/mbredel"
 
 # Install packages for building the LaTeX template.
 RUN apt-get -qq update && apt-get install -y --no-install-recommends \