use build-ko/setup-ko, go 1.19, add package comment.

Signed-off-by: Ville Aikas <vaikas@chainguard.dev>

Author: vaikas

.github/workflows/kind-scaffolding-e2e-createtree.yml

@@ -27,10 +27,10 @@ jobs:
     - uses: actions/checkout@2541b1294d2704b0964813337f33b291d3f8596b # v2.4.0
     - uses: actions/setup-go@b22fbbc2921299758641fab08929b4ac52b32923 # v2.2.0
       with:
-        go-version: '1.17'
+        go-version: '1.19'
         check-latest: true
 
-    - uses: imjasonh/setup-ko@2c3450ca27f6e6f2b02e72a40f2163c281a1f675 # v0.4
+    - uses: ko-build/setup-ko@v0.6
 
     - name: Install yq
       uses: mikefarah/yq@70403375d7b96075bd68b40c434807cff1593568 # v4.25.1

cmd/createtree-k8s/main.go

@@ -1,17 +1,21 @@
-// Copyright 2022 The Sigstore Authors
+// Copyright 2023 Google LLC. All Rights Reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
-//      http://www.apache.org/licenses/LICENSE-2.0
+//     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// Package main contains the implementation and entry point for the
+// creating a tree in Trillian and adding it into a ConfigMap.
+// More details and use cases are in:
+// ../../examples/deployment/kubernetes/README-SCAFFOLDING.md
 package main
 
 import (