Add release docs

.buildkite/release-pipeline.yml

@@ -11,6 +11,7 @@ steps:
             value: "true"
           - label: "False"
             value: "false"
+  - wait: ~
   # ----
   # Docker builds for amd64
   # ----

docs/RELEASING.md

@@ -0,0 +1,26 @@
+# Releasing
+
+The version scheme we use is **MAJOR.MINOR.PATCH** and stored in the [product_version](../product_version) file at the root of this repository.
+
+Open Crawler follows its own release versioning and does not follow the Elastic stack unified release schedule or versioning.
+
+## How to release
+
+Releasing is done entirely through Buildkite.
+The Open Crawler build can be found here: https://buildkite.com/elastic/crawler-docker-build-publish
+
+Builds will only run from a versioned branch.
+
+Build steps:
+
+1. Click `New Build`
+2. Enter a message (e.g. `x.y release`)
+3. Choose a commit
+   - the default `HEAD` is usually fine
+4. Choose a version branch with the pattern `x.y`
+   - Builds will only run from a versioned branch, you cannot build from `main`
+5. Click `Create Build`
+6. Wait a minute for the Buildkite configuration to be loaded
+   - When it has loaded, a `Build Information` button will appear
+7. Enter the build information
+8. Wait for the build to finish