Add ReadOnly option to volumeMount in Pods

[irumaru]

Added ReadOnly to the volumeMount option in Pods to support mounting of ReadOnlyMany(ROX) PVC. https://github.com/grafana/k6-operator/issues/279

The default is ReadOnly: false. The reason was to avoid destructive changes, considering the possibility that some users may already be writing to the volume in the init container.

Here are the results of a simple test. files.zip

Test Contents

• kubectl apply -f pvc.yaml to create pods to add pods and scenarios
• kubectl exec -it vp -- /bin/bash to add main.js to /mnt/vp in pods
• Create TestRun with kubectl apply -f main.yaml

result describe-log.txt and get-log.txt are the execution results. You can confirm that ReadOnly for k6-test-volume is true.