fix: stop entrypoint to fail cause dir already exists

docker/entrypoint.sh

@@ -1,6 +1,6 @@
 rm -rf agent/*
 # Copy agent jar into shared volume
-mkdir agent
+mkdir -p agent
 cp inspectit-gepard-agent.jar agent/inspectit-gepard-agent.jar
 # Keep the container running
 while true; do sleep 2; done;