Remove `crd-generator-api` Dependency After CRD Generator Fix in Fabric8 Client

[csviri]

As a workaround for issue in CRD generator for fabric8 client v6:
fabric8io/kubernetes-client#4256

had to add dependencies for crd-generator-api, like:

https://github.com/java-operator-sdk/java-operator-sdk/blob/d74559a5a87d82b00dbf993f53d9040b81b925a9/sample-operators/mysql-schema/pom.xml#L50-L53

after this issue is fixed in fabric8 client (in v6.1) , those should be removed

[csviri]

see: fabric8io/kubernetes-client#4302