fix: `cache-clear` task

[JorickPepin]

The docker_compose_run function builds the following command: ... '/bin/sh' '-c' 'exec rm -rf var/cache/ && bin/console cache:warmup'. The second part is ignored as exec replaces the current shell process, preventing any subsequent commands from being executed in the same context.

This is a quick fix, but maybe a fix at the command building level is preferable?

[lyrixx]

thanks