How to change logging-level for my Corda node running using corda-zulu docker image while using a docker compose?

To do so, you could override the command for your container. For example here it sets the logging level to DEBUG
command: /bin/bash -c "java -jar /opt/corda/bin/corda.jar --logging-level DEBUG

The image comes with a script run-corda under location (/opt/corda/bin) to start the corda jar. The Dockerfile uses this script to start the container. Thus, through the above step you override the execution of this script with the command you have specified. An example could be found here.
You can also specify any command line option as required.