Only show the first 4 characters of the secret

Signed-off-by: Mathias L. Baumann <[email protected]>

Author: Marenz

src/frequenz/client/dispatch/__main__.py

@@ -202,8 +202,8 @@ async def cli(
 
     click.echo(f"Using API URL: {url}", err=True)
     click.echo(f"Using API Key: {key}", err=True)
-    if secret:
-        click.echo(f"Using API Secret: {secret}", err=True)
+    if secret and len(secret) > 8:
+        click.echo(f"Using API Secret: {secret[:4]}{'*' * 8}", err=True)
 
     ctx.obj["client"] = DispatchApiClient(
         server_url=url,