Upgrade to operator-sdk v0.9.0

[grdryn]

For more information, see the release page:
https://github.com/operator-framework/operator-sdk/releases/tag/v0.9.0

Things that required code changes here:

• Update dependency versions in Gopkg.toml
• Update main.go for metrics changes
• Update parent UBI image tag to latest

While updating the Gopkg.toml, I took the opportunity to add the
"unused-packages = true" prune option, to try to minimise the number of
incoming files.

[psturc]

@grdryn you can add this pipeline step to use operator-sdk v0.9.0

        stage("Install Operator SDK"){
            steps{
                // qe-pipeline-library step
                installOperatorSdk version: "v0.9.0"
            }
            post{
                failure{
                    echo "====++++'Install Operator SDK' execution failed++++===="
                    echo "Please check if the version of operator-sdk you provided exists"
                    echo "https://github.com/operator-framework/operator-sdk/releases"
                }
        
            }
        }

It will replace the existing operator-sdk binary. I'll keep the default binary (v0.8.1) on the slave for now and update all operator repositories with the change we discussed when it's less busy there. (To always download operator-sdk binary during build).

[grdryn]

Closing this as it's superseded by #72