Fix ENVs to use "key=value" format (#234) (#250)

Co-authored-by: Aaron Marburg <amarburg@uw.edu>
(cherry picked from commit 368b25a)

Co-authored-by: Aaron Marburg <amarburg@apl.washington.edu>

Author: mergify[bot]

.docker/Dockerfile

@@ -250,6 +250,6 @@ RUN sudo apt-get update \
     && sudo rm -rf /var/lib/apt/lists/*
 
 # Env vars for the nvidia-container-runtime.
-ENV NVIDIA_VISIBLE_DEVICES all
-ENV NVIDIA_DRIVER_CAPABILITIES graphics,utility,compute
-ENV QT_X11_NO_MITSHM 1
+ENV NVIDIA_VISIBLE_DEVICES=all
+ENV NVIDIA_DRIVER_CAPABILITIES=graphics,utility,compute
+ENV QT_X11_NO_MITSHM=1