docs: clarify build and release process (#13)

Author: hknutsen

CONTRIBUTING.md

@@ -10,8 +10,17 @@ This document provides guidelines for contributing to this project.
 
 1. Create a new branch. For external contributors, create a fork.
 
-1. Make your changes.
-
+1. Make your changes to `main.bicep`.
 1. Commit your changes.
 
+   Use the [Conventional Commits](https://www.conventionalcommits.org/en/v1.0.0/) specification for semantic commit messages.
+
 1. Create a pull request to merge your changes into the `main` branch.
+
+   This will trigger a [build workflow run](https://github.com/equinor/azure-terraform-backend-template/actions/workflows/build.yml) that builds `azuredeploy.json`.
+
+1. Request a review.
+
+1. Once approved, merge the pull request.
+
+   This will trigger a [release workflow run](https://github.com/equinor/azure-terraform-backend-template/actions/workflows/release.yml) that creates a new GitHub release.