add docs for polaris audit --quiet option

docs/cli.md

@@ -56,6 +56,7 @@ webhook
     --only-show-failed-tests          If specified, audit output will only show failed tests.
     --output-file string              Destination file for audit results.
     --output-url string               Destination URL to send audit results.
+    --quiet                           Suppress the 'upload to Insights' prompt.
     --resource string                 Audit a specific resource, in the format namespace/kind/version/name, e.g. nginx-ingress/Deployment.apps/v1/default-backend.
     --set-exit-code-below-score int   Set an exit code of 4 when the score is below this threshold (1-100).
     --set-exit-code-on-danger         Set an exit code of 3 when the audit contains danger-level issues.