Fix Get Function Cluster in Master Docs (#2960)
Fix Get Function Cluster in Master Docs (#2960)

### Motivation

About #2948 , fix path in master docs.

### Modifications
Change `curl -s http://localhost:8080/admin/v2/functions/cluster` to `curl -s http://localhost:8080/admin/v2/worker/cluster`
massakam/pulsar,massakam/pulsar,nkurihar/pulsar,ArvinDevel/incubator-pulsar,ArvinDevel/incubator-pulsar,yahoo/pulsar,jai1/pulsar,yahoo/pulsar,merlimat/pulsar,nkurihar/pulsar,merlimat/pulsar,yahoo/pulsar,nkurihar/pulsar,massakam/pulsar,merlimat/pulsar,ArvinDevel/incubator-pulsar,nkurihar/pulsar,merlimat/pulsar,jai1/pulsar,jai1/pulsar,yahoo/pulsar,massakam/pulsar,nkurihar/pulsar,yahoo/pulsar,nkurihar/pulsar,nkurihar/pulsar,ArvinDevel/incubator-pulsar,jai1/pulsar,ArvinDevel/incubator-pulsar,ArvinDevel/incubator-pulsar,massakam/pulsar,jai1/pulsar,nkurihar/pulsar,massakam/pulsar,jai1/pulsar,ArvinDevel/incubator-pulsar,ArvinDevel/incubator-pulsar,merlimat/pulsar,merlimat/pulsar,nkurihar/pulsar,yahoo/pulsar,jai1/pulsar,jai1/pulsar,jai1/pulsar