improve release notes tool

Improve release notes generation by adding empty section for
superseded or reverted PRs, aligning empty line addition between image
tag and thanking our contributors to same as BMO and CAPM3.

Author: tuminoid

hack/tools/release/notes.go

@@ -1,7 +1,8 @@
+//go:build tools
 // +build tools
 
 /*
-Copyright 2019 The Kubernetes Authors.
+Copyright 2021 The Kubernetes Authors.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -41,6 +42,7 @@ const (
 	warning       = ":warning: Breaking Changes"
 	other         = ":seedling: Others"
 	unknown       = ":question: Sort these by hand"
+	superseded    = ":recycle: Superseded or Reverted"
 )
 
 var (
@@ -51,6 +53,7 @@ var (
 		documentation,
 		other,
 		unknown,
+		superseded,
 	}
 
 	fromTag = flag.String("from", "", "The tag or commit to start from.")
@@ -92,8 +95,8 @@ func firstCommit() string {
 }
 
 func run() int {
-	latestTag := latestTag()
 	lastTag := lastTag()
+	latestTag := latestTag()
 	cmd := exec.Command("git", "rev-list", lastTag+"..HEAD", "--merges", "--pretty=format:%B")
 
 	merges := map[string][]string{
@@ -103,6 +106,7 @@ func run() int {
 		warning:       {},
 		other:         {},
 		unknown:       {},
+		superseded:    {},
 	}
 	out, err := cmd.CombinedOutput()
 	if err != nil {
@@ -170,6 +174,9 @@ func run() int {
 		merges[key] = append(merges[key], formatMerge(body, prNumber))
 	}
 
+	// Add empty superseded section
+	merges[superseded] = append(merges[superseded], "- `<insert superseded bumps and reverts here>`")
+
 	// TODO Turn this into a link (requires knowing the project name + organization)
 	fmt.Printf("Changes since %v\n---\n", lastTag)
 
@@ -184,9 +191,8 @@ func run() int {
 		}
 	}
 
-	fmt.Printf("The image for this release is: %v\n", latestTag)
-	fmt.Println("")
-	fmt.Println("_Thanks to all our contributors!_ 😊")
+	fmt.Printf("The container image for this release is: %v\n", latestTag)
+	fmt.Println("\nThanks to all our contributors! 😊")
 
 	return 0
 }