chore: switch base image to ghcr.io/tektoncd/plumbing/static-base (#1702)

Replace ghcr.io/wolfi-dev/static:alpine with the Tekton-maintained static base
image built in tektoncd/plumbing. Supports all four target architectures
(amd64, arm64, s390x, ppc64le) and is rebuilt daily.

Related: tektoncd/pipeline#9557, tektoncd/plumbing#3434

Author: vdemeester

.ko.yaml

@@ -1,4 +1,2 @@
 ---
-# The default base image, cgr.dev/chainguard/static, no longer provides all the platforms the Chains
-# controller claims support for.
-defaultBaseImage: ghcr.io/wolfi-dev/static:alpine
+defaultBaseImage: ghcr.io/tektoncd/plumbing/static-base@sha256:e150c89001e336b6a0200a6bac766a7b455e5573bf91c6c37f3ef8cf2fdccf0a