Groovy Expression for pipeline

I would like to use this plugin in some more advanced scenarios.
For example
- I would like to take all resources with label but with specific description
- I would like to exclude some resources
- I would like that every retry to lock different resource
retry(3) {
lock(label: "LABEL", variable: "VARIABLE", quantity: 1) {
def v = VARIABLE // never the same
}
}

I would be able to handle every case with groovy expression for lock block.

Start with the lock(label: "LABEL", variable: "VARIABLE", quantity: 1) block and the surrounding retry(3) example in the issue. Clarify how Groovy expressions should select resources by label and description, exclude resources, and select a different resource on each retry; done means these scenarios are supported by the pipeline lock block.

Written by the indexing model from the issue text.