Fix 1539: Helm v2.17.0 and set default value for stablerepourl

The --skip-repo option was not available. The version v2.17.0 is the
latest v2 version available.

Set https://charts.helm.sh/stable as the default stablerepourl value.

Change-Id: Ifdd85f0f891a705f56cdd50c6e4dbf95820d706f
Signed-off-by: David Garcia <david.garcia@canonical.com>
(cherry picked from commit 1d5c221862067b3b5b6e0555dcc4eb6c34e9a9f9)
diff --git a/installers/charm/lcm/src/charm.py b/installers/charm/lcm/src/charm.py
index 4e0b4be..9b025c9 100755
--- a/installers/charm/lcm/src/charm.py
+++ b/installers/charm/lcm/src/charm.py
@@ -108,6 +108,7 @@
     vca_model_config_test_mode: Optional[bool]
     vca_model_config_transmit_vendor_metrics: Optional[bool]
     vca_model_config_update_status_hook_interval: Optional[str]
+    vca_stablerepourl: Optional[str]
 
     @validator("log_level")
     def validate_log_level(cls, v):
@@ -191,6 +192,7 @@
                 "OSMLCM_STORAGE_COLLECTION": "files",
                 "OSMLCM_STORAGE_URI": config.mongodb_uri
                 or self.mongodb_client.connection_string,
+                "OSMLCM_VCA_STABLEREPOURL": config.vca_stablerepourl,
             }
         )
         if config.vca_host: