Add minimum Kubernetes version supported

Add the supported minimum Kubernetes version into the application
metadata file.

The minimum Kubernetes version is set to 1.24.4 and should be changed
accordingly for future application updates.

The "supported_k8s_version:minimum" field is optional but it will become
mandatory in the near future.

This also contains a fix to properly trigger the Tox metadata checks.

Test Plan
PASS: build-pkgs && build-image
PASS: Apply application

Story: 2010929
Task: 49507

Change-Id: I6d698b94cf7008f574d4170e3bd1a8d494d5e619
Signed-off-by: Igor Soares <Igor.PiresSoares@windriver.com>

.zuul.yaml

@@ -50,8 +50,6 @@
       - starlingx/update
       - starlingx/utilities
       - starlingx/root
-    files:
-      - python3-k8sapp-vault/*
     vars:
       tox_envlist: metadata
       tox_extra_args: -c python3-k8sapp-vault/k8sapp_vault/tox.ini

stx-vault-helm/stx-vault-helm/files/metadata.yaml

@@ -6,3 +6,6 @@ maintain_user_overrides: true
 
 upgrades:
   auto_update: true
+
+supported_k8s_version:
+  minimum: 1.24.4