Backport of add script to generate changelog for a PR into release/1.19.x (#21723)

* backport of commit fd95026739

* backport of commit 24684b3ae6

* backport of commit e7993e328b

* backport of commit f235582563

* backport of commit 0dbf48e15b

---------

Co-authored-by: jm96441n <john.maguire@hashicorp.com>

Makefile

@@ -620,6 +620,14 @@ envoy-regen: ## Regenerating envoy golden files
 	@find "command/connect/envoy/testdata" -name '*.golden' -delete
 	@go test -tags '$(GOTAGS)' ./command/connect/envoy -update
 
+
+##@ Changelog
+
+.PHONY: gen-changelog
+gen-changelog: ## Generate changelog entry for the current branch based on the currently open PR for that branch
+	@$(SHELL) $(CURDIR)/build-support/scripts/gen-changelog.sh
+
+	
 ##@ Help
 
 # The help target prints out all targets with their descriptions organized
@@ -635,3 +643,4 @@ envoy-regen: ## Regenerating envoy golden files
 .PHONY: help
 help: ## Display this help.
 	@awk 'BEGIN {FS = ":.*##"; printf "\nUsage:\n  make \033[36m<target>\033[0m\n"} /^[a-zA-Z_0-9-]+:.*?##/ { printf "  \033[36m%-15s\033[0m %s\n", $$1, $$2 } /^##@/ { printf "\n\033[1m%s\033[0m\n", substr($$0, 5) } ' $(MAKEFILE_LIST)
+

build-support/scripts/gen-changelog.sh

@@ -0,0 +1,73 @@
+#! /bin/bash
+# Copyright (c) HashiCorp, Inc.
+# SPDX-License-Identifier: BUSL-1.1
+
+set -eo pipefail
+
+pr_number=$(gh pr list -H "$(git rev-parse --abbrev-ref HEAD)" -q ".[0].number" --json "number")
+
+# check if this changelog is referencing an enterprise change
+curdir=$(pwd)
+
+filename = ".changelog/$pr_number.txt"
+if [[ ! $curdir == *"enterprise"* ]]; then
+  is_enterprise = "n"
+  read -p "Is this an enterprise PR? (y/n): " is_enterprise
+
+  if [[ $is_enterprise == "y" ]]; then
+    filename = ".changelog/_$pr_number.txt"
+  fi
+else
+  filename = ".changelog/_$pr_number.txt"
+fi
+
+# create a new changelog file
+touch $filename
+
+echo "Created a new changelog file for PR $pr_number."
+
+# prompt user to pick from list of types of changlog from "breaking-change", "security", "feature", "deprecation", or "bug"
+echo "Please select the type of change:"
+echo "1. breaking-change"
+echo "2. security"
+echo "3. feature"
+echo "4. deprecation"
+echo "5. bug"
+
+if [ -z "$1" ]; then
+  read -p "Enter your choice: " choice
+else
+  choice=$1
+fi
+
+type=""
+
+case $choice in
+1)
+  type="breaking-change"
+  ;;
+2)
+  type="security"
+  ;;
+3)
+  type="feature"
+  ;;
+4)
+  type="deprecation"
+  ;;
+5)
+  type="bug"
+  ;;
+*)
+  echo "Invalid choice. Please select a number from 1 to 5."
+  exit 1
+  ;;
+esac
+
+msg=""
+
+read -ep $'Please enter the changelog message:\n' msg
+
+echo -e "\`\`\`release-note:$type\n$msg\n\`\`\`" >>"$filename"
+
+cat .changelog/$pr_number.txt