Merge pull request #1048 from justaugustus/kube-cross

build-image: Promote kube-cross:v1.15.0-beta.1-1

Author: k8s-ci-robot

k8s.gcr.io/images/k8s-staging-build-image/images.yaml

@@ -89,6 +89,7 @@
     "sha256:268c0a52333449a4e0a10847149ea3d3d1c31ed32552c4269a7a7edc1cd0e908": ["v1.14.6-1"]
     "sha256:33f9733e0f3b052447a2261b1822a42376ca20cda675b57baaf6dfabee829deb": ["v1.14.5-2"]
     "sha256:3b963befb3b660a859f51bc8212ff72a9ded9ff1495829c4d9cc4bbf676c80d8": ["v1.13.9-1"]
+    "sha256:575a2340e74461fd3203fcab15665db391235e7c0777259cdc82c5c705ebb128": ["v1.15.0-beta.1-1"]
     "sha256:5eb52c034d83601b9deec0a682e76954fd86aa775d71ece7b6e6a099cd9aaea7": ["v1.14.5-1"]
     "sha256:61c8895e2957cd094311a907daa15c2bed8ecb84eed73e62de2888441e6fb1b5": ["v1.14.1-1"]
     "sha256:61ec8db3ddcb577987ce0165818cfe269eda32a9d27127657c744ff94773a31c": ["v1.13.9-5"]