Commit summary: 0979c09 prow.sh: fix E2E suite for Kubernetes >= 1.18 3b4a2f1 prow.sh: fix installing Go for Kubernetes 1.19.0 82d108a switch to Go 1.15 843bddc Add steps on promoting release images
$ git subtree pull --prefix=release-tools https://github.com/kubernetes-csi/csi-release-tools.git master
git-subtree-dir: release-tools git-subtree-mainline: 21ce5ebe0356781b55e4940ae4b03c267822dcdc git-subtree-split: 33d58fdc29b90120bf16e536042379251f8631f2