Use gren to generate release notes

See https://github.com/github-tools/github-release-note for details

.grenrc.yaml

@@ -0,0 +1,9 @@
+dataSource: "issues"
+prefix: ""
+onlyMilestones: false
+groupBy:
+  "Enhancements": ["enhancement"]
+  "Bug Fixes": ["bug"]
+changelogFilename: "CHANGELOG.md"
+template:
+  issue: "- {{name}} [{{text}}]({{url}})"

README.md

@@ -1,6 +1,7 @@
 # Steeltoe NetCoreToolTemplates
 
 [![Build Status](https://dev.azure.com/SteeltoeOSS/Steeltoe/_apis/build/status/Initializr/SteeltoeOSS.NetCoreToolTemplates?branchName=main)](https://dev.azure.com/SteeltoeOSS/Steeltoe/_build/latest?definitionId=46&branchName=main)
+[![Automated Release Notes by gren](https://img.shields.io/badge/%F0%9F%A4%96-release%20notes-00B2EE.svg)](https://github-tools.github.io/github-release-notes/)
 
 Steeltoe NetCoreToolTemplates is a collection of .NET Core Tool templates.