Add missing cache hook for argocd

With this when running drenv cache, we refresh the argocd cache.

Example usage:

    $ drenv cache envs/argocd.yaml
    2024-06-20 16:31:14,728 INFO    [argocd] Refreshing cached addons
    2024-06-20 16:31:14,729 INFO    [argocd] Running addons/argocd/cache
    2024-06-20 16:31:15,973 INFO    [argocd] addons/argocd/cache completed in 1.24 seconds
    2024-06-20 16:31:15,974 INFO    [argocd] Cached addons refreshed in 1.25 seconds

Signed-off-by: Nir Soffer <nsoffer@redhat.com>

test/addons/argocd/cache

@@ -0,0 +1,10 @@
+#!/usr/bin/env python3
+
+# SPDX-FileCopyrightText: The RamenDR authors
+# SPDX-License-Identifier: Apache-2.0
+
+import os
+from drenv import cache
+
+os.chdir(os.path.dirname(__file__))
+cache.refresh(".", "addons/argocd-2.11.yaml")