FIX solve legacy warning

dockerfiles/devenv.Dockerfile

@@ -2,13 +2,13 @@
 # *              DEVENV Base Image for ROS                  *
 # ***********************************************************
 
-ARG ROS_DISTRO
+ARG ROS_DISTRO=
 FROM osrf/ros:${ROS_DISTRO}-desktop-full as devenv
-ENV ROS_DISTRO "${ROS_DISTRO}"
+ENV ROS_DISTRO="${ROS_DISTRO}"
 
 ARG EXT_SHELL=bash
-ENV EXT_SHELL "${EXT_SHELL}"
-ENV SHELL "/bin/${EXT_SHELL}"
+ENV EXT_SHELL="${EXT_SHELL}"
+ENV SHELL="/bin/${EXT_SHELL}"
 RUN echo "Building devenv for ROS" $ROS_DISTRO "with shell" $EXT_SHELL
 
 # Avoid warnings by switching to noninteractive
@@ -25,9 +25,9 @@ RUN apt-get update && apt-get install -y apt-utils
 RUN apt-get install -y \
     locales \
     && sed -i '/en_US.UTF-8/s/^# //g' /etc/locale.gen && locale-gen en_US.UTF-8
-ENV LANG en_US.UTF-8
-ENV LANGUAGE en_US:en
-ENV LC_ALL en_US.UTF-8
+ENV LANG=en_US.UTF-8
+ENV LANGUAGE=en_US:en
+ENV LC_ALL=en_US.UTF-8
 
 # Configure apt and install base packages
 RUN apt-get update && \
@@ -121,7 +121,7 @@ COPY ./ros_entrypoint.sh /
 RUN chmod a+x /ros_entrypoint.sh
 
 # Set running in docker for zsh powerlevel10k
-ENV RUNNING_IN_DOCKER true
+ENV RUNNING_IN_DOCKER=true
 
 # Define entrypoint and command
 ENTRYPOINT ["/ros_entrypoint.sh"]