added signature notes

build-alpine.jenkins

@@ -4,6 +4,15 @@ def repository = "registry.c.test-chamber-13.lan"
 def kanikoImage = "${repository}/library/kaniko:latest"
 def repositoryCreds = "harbor-repository-creds"
 
+// Notes:
+// Don't bother trying to sign images with kaniko. It's not supported.
+//
+// Cosign is an option but won't be recgonized by harbor and other
+// docker registries.
+//
+// You can sign images with docker, but that requires Docker-in-docker,
+// and Docker-in docker requires the --priviledged flag to run.
+
 podTemplate(
 	label: label,
 	name: "pipeline-worker",