Deprecate fleets command in favor of fleet list

Change-type: patch

docs/balena-cli.md

@@ -2573,7 +2573,7 @@ produce JSON output instead of tabular output
 
 ### Aliases
 
-- `fleets`
+- `fleets` *(deprecated)*
 
 
 To use one of the aliases, replace `fleet list` with the alias.

src/commands/fleet/list.ts

@@ -28,6 +28,7 @@ interface ExtendedApplication extends ApplicationWithDeviceTypeSlug {
 
 export default class FleetListCmd extends Command {
 	public static aliases = ['fleets'];
+	public static deprecateAliases = true;
 
 	public static description = stripIndent`
 		List all fleets.