update dockerfile to use equals syntax for environment variables

Author: leighmcculloch

Dockerfile

@@ -15,7 +15,7 @@ FROM $LAB_IMAGE_REF AS lab
 FROM ubuntu:22.04
 
 ARG REVISION
-ENV REVISION $REVISION
+ENV REVISION=$REVISION
 
 EXPOSE 5432
 EXPOSE 6060
@@ -62,6 +62,6 @@ RUN ["chmod", "+x", "start"]
 
 ARG PROTOCOL_VERSION_DEFAULT
 RUN test -n "$PROTOCOL_VERSION_DEFAULT" || (echo "Image build arg PROTOCOL_VERSION_DEFAULT required and not set" && false)
-ENV PROTOCOL_VERSION_DEFAULT $PROTOCOL_VERSION_DEFAULT
+ENV PROTOCOL_VERSION_DEFAULT=$PROTOCOL_VERSION_DEFAULT
 
 ENTRYPOINT ["/start"]