alfresco-global.properties can still be found under $TOMCAT_HOME/shared/classes/alfresco-global.properties (i.e. /usr/local/tomcat/shared/classes/alfresco-global.properties) in alfresco repository container.
When all your containers are up, you can run following command to see the launced container names/ids.
You can connect to repository container and navigate to '/usr/local/tomcat/shared/classes' directory to find the alfresco-global.properties file.
For example container name is: 'acs_community_alfresco_1' then you can use following command to connect and find the file.
However, this file (/usr/local/tomcat/shared/classes/alfresco-global.properties) may be empty and may not have any properties in it.
You can either have your 'alfresco-global.properties' and copy it to repository container while launching the containers with help of DockerFile or use JAVA_OPTS within 'docker-compose.yml' file to add/update any properties which you would like.
This project has examples of DockerFile and JAVA_OPTS based examples, if you want to take a reference: