add more retrys for NVD provider (#443)

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

.vunnel.yaml

@@ -13,3 +13,10 @@ providers:
     # apply community-provided overrides to the NVD data
     # sourced from the https://github.com/anchore/nvd-data-overrides repo
     overrides_enabled: true
+
+    # we're getting a lot of 503s and intermittent failures from the NVD API, so we're going to retry a few times
+    request_timeout: 250
+    runtime:
+      on_error:
+        retry_count: 10
+        retry_delay: 60