[docker/cli] Deprecated project ScatterHQ/Flocker given as example in docs/extend/plugins_volume.md

### ROOT CAUSE The issue arises because the Docker CLI documentation includes an example using the Flocker plugin, which is deprecated and archived. This outdated example should be replaced with a current, functional plugin to provide accurate guidance to users. ### CODE FIX 1. **Remove Flocker Example**: Delete the Flocker example from `docs/extend/plugins_volume.md` and `docs/extend/legacy_plugins.md`. 2. **Add Example with a Current Plugin**: Replace the Flocker example with a modern volume plugin example using the `local` driver (built-in to Docker) for clarity and relevance. Here are the code changes: **Changes to `docs/extend/plugins_volume.md`**: ```markdown ### Example: Local Volume Plugin The following example shows how to use the local volume plugin. ```json { "Name": "local", "Driver": "local", "Options": { "size": "10G" } } ``` **Changes to `docs/extend/legacy_plugins.md`**: ```markdown ### Historical Example: Flocker The Flocker plugin is deprecated. This example is provided for historical context. ```json { "Name": "flocker", "Driver": "flocker", "Options": { "size": "10G" } } ``` **Steps to Apply the Fix**: 1. Update `docs/extend/plugins_volume.md` by replacing the Flocker example with the `local` driver example. 2. Update `docs/extend/legacy_plugins.md` by adding the Flocker example under the "Historical Examples" section. 3. Remove any other occurrences of Flocker in the documentation. This ensures the documentation remains accurate and useful by focusing on current, maintained plugins.