chore: Remove old release workflows and update CHANGELOG link (#72)

Author: morgante

.github/workflows/generate-changelog.yaml

@@ -1,6 +1,6 @@
 # Changelog
 
-All notable changes to this project will be documented in this file. See [standard-version](https://github.com/conventional-changelog/standard-version) for commit guidelines.
+All notable changes to this project will be documented in this file. See [conventional-commits](https://www.conventionalcommits.org/) for commit guidelines.
 
 ### [1.4.1](https://github.com/terraform-google-modules/terraform-google-vm/compare/v1.4.0...v1.4.1) (2020-01-21)