Update release process documentation

Signed-off-by: Angel Misevski <amisevsk@redhat.com>

Author: amisevsk

docs/release/README.md

@@ -6,19 +6,38 @@ This document contains the instructions for the DevWorkspace Operator release pr
 
 The release process is powered by the 'Release DevWorkspace Operator' [GitHub Action](https://github.com/devfile/devworkspace-operator/actions/workflows/release.yml).
 
-In order to release a new version of the DevWorkspace Operator:
-
-1. Trigger the prerelease by running the action using the workflow from the `main` branch. Provide the version in format `v0.y.z` e.g. `v0.13.0` and set `true` for the prelease field:
+### Preparing release branch
+Trigger the prerelease by running the 'Release DevWorkspace Operator' action using the workflow from the `main` branch. Provide the version in format `v0.y.z` e.g. `v0.13.0` and set `true` for the prelease field:
 
 ![Prerelease](prerelease.png?raw=true "Prerelease")
 
 The action will create the dedicated release branch e.g. `0.13.x` and the prelease commit e.g https://github.com/devfile/devworkspace-operator/commit/4905c6c695e4d4945a3810df9a46a5ecf11d09f1 
 
-> :warning: If necessary, cherry-pick any additional fixes to the release branch.
+This step is required for every new minor release of the DevWorkspace Operator.
+
+### Testing prerelease artifacts
+
+The release job updates the yaml files used to deploy the DevWorkspace Operator to use the new images. However, for commits that aren't tagged for release, these yaml files will refer to still-unbuilt container images. For example, commits in the `0.15.x` branch will use `quay.io/devfile/devworkspace-controller:v0.15.0`, but that image will only be pushed once the full release happens.
+
+This means that to test commits in a release branch before running the release job, it's necessary to manually build all DevWorkspace Operator images and override them in the deployment:
+
+```bash
+export DWO_IMG=quay.io/yourrepo/devworkspace-controller:prerelease
+export PROJECT_CLONE_IMG=quay.io/yourrepo/project-clone:prerelease
+# build and push project clone image
+podman build -t "$PROJECT_CLONE_IMG" -f ./project-clone/Dockerfile .
+podman push "$PROJECT_CLONE_IMG"
+# build and push DevWorkspace Operator image
+make docker
+# deploy DevWorkspace Operator using these images
+make install
+```
 
-Build the image from the `0.13.x` branch and run manually a test with DevWorkspace startup against this version of the operator. If the workspace is started without errors you can proceed with the release.
+### Releasing a new version
 
-2. Trigger the release by running the same action using the workflow from the branch that was created during the previous step e.g. `0.13.x`. Provide the version in format `v0.y.z` e.g. `v0.13.0` and set `false` for the prelease field:
+> :warning: If necessary, cherry-pick any additional fixes to the release branch.
+
+Trigger the release by running the 'Release DevWorkspace Operator' action using the workflow from the release branch that was created in the pre-release setup, e.g. `0.13.x`. Provide the version in format `v0.y.z`, e.g. `v0.13.0` and set `false` for the prelease field:
 
 ![Release](release.png?raw=true "Release")
 
@@ -31,3 +50,13 @@ The action will create the release commit with the new OLM bundle e.g. https://g
 The index image with the `release` tag is also pushed automatically to quay.io:
 
 - https://quay.io/repository/devfile/devworkspace-operator-index?tag=release&tab=tags
+
+After releasing a new version of the DevWorkspace Operator, it is necessary to copy the bundle files generated for that release to the main branch by opening a PR.
+
+### Creating a bugfix release
+
+To create a bugfix release, the process is the same as [releasing](#releasing-a-new-version) above:
+
+1. Cherry-pick any commits required for the bugfix release
+2. Trigger the 'Release DevWorkspace Operator' action using the release branch (e.g. `0.13.x`), with `prerelease: false`
+3. Open a PR to add the bundle files created for the new release to the main branch.