Promote latest csi-external-health-monitor-controller version

Author: nixpanic

registry.k8s.io/images/k8s-staging-sig-storage/images.yaml

@@ -42,6 +42,7 @@
     "sha256:97e806babd29424737464aaafdc3ede91119c077ddc0b7ecf423c5dca4833d84": [ "v0.12.1" ]
     "sha256:160f1906b49914e544a68d96a97eaa71107b600cee883b60ce1ab9c71d02ae63": [ "v0.13.0" ]
     "sha256:65d118e955cfa0827d0f727fe161a7469e0e1c6829c347a484130aeb6e45f377": [ "v0.14.0" ]
+    "sha256:ce054c6fade575e9d4dbd4c3d65b9c5d1b05160aacfb9cf8d8cac51d73f3ccea": [ "v0.15.0" ]
     "sha256:14988b598a180cc0282f3f4bc982371baf9a9c9b80878fb385f8ae8bd04ecf16": [ "v0.2.0" ]
     "sha256:46346c621c4d7e0976ddfb1e8722f1eb0af4e32a1d9648228b04364d9d4830ec": [ "v0.3.0" ]
     "sha256:9f1a8723e54c343a76f6f5691428fae9e1e617c213013318100cbdf00d544501": [ "v0.4.0" ]