cos-gpu-installer: Release v2.5.6

This includes the changes from
https://cos-review.git.corp.google.com/c/cos/tools/+/110701

BUG=b/428981220
TEST=presubmit, `sudo COS_GPU_INSTALLER=us.gcr.io/cloud-kernel-build/cos-gpu-installer:latest cos-extensions install gpu -- --version R535 --gcs-download-bucket=cos-infra-prod-artifacts-presubmit --gcs-download-prefix=lakitu-release-tryjob/R117-18613.339.65-c6ab4675 --gdr --debug --test`
RELEASE_NOTE=None

Change-Id: Ie2f45eb1a0caf75f0e4494c45cb917f773b5fe7b
Reviewed-on: https://cos-review.googlesource.com/c/cos/tools/+/111461
Cloud-Build: GCB Service account <228075978874@cloudbuild.gserviceaccount.com>
Reviewed-by: Kevin Berry <kpberry@google.com>
Tested-by: Chenglong Tang <chenglongtang@google.com>
diff --git a/release/release-versions.yaml b/release/release-versions.yaml
index dcc7d84..80995fa 100644
--- a/release/release-versions.yaml
+++ b/release/release-versions.yaml
@@ -29,9 +29,9 @@
   multi-arch: false
 - staging_container_name: "cos-gpu-installer"
   release_container_name: "cos-gpu-installer"
-  build_tag: "6c2cbdb-0f640a5e-3abf-4eaf-a39d-001b35dcdced"
+  build_tag: "01cf591-9b4235e5-8d5c-4bc3-a6cf-f44ac8fda9c8"
   release_tags:
-    - "v2.5.5"
+    - "v2.5.6"
   multi-arch: true
 - staging_container_name: "cos-gpu-driver-builder"
   release_container_name: "cos-gpu-driver-builder"