Add release process (#783)

Author: lucacome

release-process.md

@@ -0,0 +1,45 @@
+# Release Process
+
+This document outlines the steps involved in the release process for the NGINX Prometheus Exporter.
+
+<!-- START doctoc generated TOC please keep comment here to allow auto update -->
+<!-- DON'T EDIT THIS SECTION, INSTEAD RE-RUN doctoc TO UPDATE -->
+## Table of Contents
+
+- [Versioning](#versioning)
+- [Release Planning and Development](#release-planning-and-development)
+- [Releasing a New Version](#releasing-a-new-version)
+
+<!-- END doctoc generated TOC please keep comment here to allow auto update -->
+
+## Versioning
+
+The project follows [Semantic Versioning](https://semver.org/).
+
+## Release Planning and Development
+
+The features that will go into the next release are reflected in the
+corresponding [milestone](https://github.com/nginxinc/nginx-prometheus-exporter/milestones). Refer to
+the [Issue Lifecycle](/ISSUE_LIFECYCLE.md) document for information on issue creation and assignment to releases.
+
+## Releasing a New Version
+
+1. Create an issue to define and track release-related activities. Choose a title that follows the
+   format `Release X.Y.Z`.
+2. Stop merging any new work into the main branch.
+3. Check the release draft under the [GitHub releases](https://github.com/nginxinc/nginx-prometheus-exporter/releases) page
+to ensure that everything is in order.
+4. Create a PR to update the version in the `Makefile` and [README](README.md) to the new version, and any other necessary
+   changes.
+5. Once the PR is merged, create a new release tag in the format `vX.Y.Z`:
+
+    ```bash
+    git tag -a vX.Y.Z -m "Release vX.Y.Z"
+    git push origin vX.Y.Z
+    ```
+
+    As a result, the CI/CD pipeline will:
+    - Build the Docker image and push it to the registries.
+    - Publish the release to Snapcraft, Homebrew, Scoop, and Nix.
+    - Create a GitHub release with the autogenerated changelog and artifacts attached.
+    - Announce the release in the community Slack.