Add 2A upgrade documentation (#41)

Closes: K0rdent/kcm#399

docs/usage/2a-upgrade.md

@@ -0,0 +1,52 @@
+# Upgrading 2A to the newer version
+
+> NOTE: To upgrade 2A the user must have `Global Admin` role.
+> For the detailed information about 2A RBAC, refer to the [RBAC documentation](../rbac/roles.md).
+
+Follow the steps below to update 2A to a newer version:
+
+**Step 1. Create a New `Release` Object**
+
+Create a `Release` object in the management cluster for the desired version. For example, to create
+a `Release` for version `v0.0.4`, run the following command:
+
+```shell
+VERSION=v0.0.4
+kubectl create -f https://github.com/Mirantis/hmc/releases/download/${VERSION}/release.yaml
+```
+
+**Step 2. Update the `Management` Object with the New `Release`**
+
+- List available `Releases`:
+
+To view all available `Releases`, run:
+
+```shell
+kubectl get releases
+```
+
+Example output:
+
+```shell
+NAME        AGE
+hmc-0-0-3   71m
+hmc-0-0-4   65m
+```
+
+- Patch the `Management` Object with the New `Release` Name:
+
+Update the `spec.release` field in the `Management` object to point to the new release. Replace `hmc-0-0-4` with
+the name of your new release:
+
+```shell
+RELEASE_NAME=hmc-0-0-4
+kubectl patch management.hmc hmc --patch "{\"spec\":{\"release\":\"${RELEASE_NAME}\"}}" --type=merge
+```
+
+**Step 3. Verify the Upgrade**
+
+Check the status of the `Management` object to monitor the readiness of the components:
+
+```shell
+kubectl get management.hmc hmc -o=jsonpath={.status} | jq
+```

mkdocs.yml

@@ -79,6 +79,7 @@ nav:
       - Air-gapped Installation Guide: usage/airgap.md
       - Create Managed Cluster: usage/create-managed-cluster.md
       - Cluster Updates: usage/cluster-update.md
+      - 2A Upgrade: usage/2a-upgrade.md
   - Templates:
       - Overview: template/main.md
       - BYO Templates: template/byo-templates.md