docs: clarify docker compose upgrade

docs/MigratePrometheusDocker.md

@@ -65,7 +65,8 @@ docker volume create --name harvest_prometheus_data
 ## Copy the historical Prometheus data
 
 We will copy the historical Prometheus data from the old volume to the new one by
-mounting both volumes and copying data between them.
+mounting both volumes and copying data between them. **NOTE**: Prometheus only supports copying a single volume. It will
+not work if you attempt to copy multiple volumes into the same destination volume.
 
 ```bash
 # replace  `HISTORICAL_VOLUME` with the name of the Prometheus volume that contains you historical data found in step 2.

docs/install/containers.md

@@ -140,20 +140,21 @@ docker-compose -f prom-stack.yml -f harvest-compose.yml down
 
 > Note: If you want to keep your historical Prometheus data, and you set up your Docker Compose workflow before
 > Harvest `22.11`, please read how
-> to [migrate your Prometheus volume](https://github.com/NetApp/harvest/blob/main/docs/MigratePrometheusDocker.md) before
-> continuing with the upgrade steps below.
+> to [migrate your Prometheus volume](https://github.com/NetApp/harvest/blob/main/docs/MigratePrometheusDocker.md)
+> before continuing with the upgrade steps below.
 
 To upgrade Harvest:
 
 1. Download the latest `tar.gz` or packaged version and install it.
    This is needed since the new version may contain new templates, dashboards, or other files not included in the Docker
    image.
 
-2. Check the release notes to see if there are new features or fixes in the `harvest docker generate` command you want
-   to take advantage of.
-   If so, regenerate your Docker compose file(s).
+2. Copy your existing `harvest.yml` into the new Harvest directory created in step #1.
 
-3. Pull new images and restart your containers like so:
+3. Regenerate your `harvest-compose.yml` file by
+   running `bin/harvest generate docker full --port --output harvest-compose.yml`
+
+4. Pull new images and restart your containers like so:
 
 ```
 docker pull cr.netapp.io/harvest   # or if using Docker Hub: docker pull rahulguptajss/harvest