source-amazon-ads: bump version to 7.3.1 (#356)

This is the last version published before the connector was relicensed
to ELv2 on 2025-07-22, so we are unable to upgrade it further.

Author: nicolaslazo

airbyte-integrations/connectors/source-amazon-ads/Dockerfile

@@ -1,7 +1,7 @@
 ARG AIRBYTE_TO_FLOW_TAG="dev"
 FROM ghcr.io/estuary/airbyte-to-flow:$AIRBYTE_TO_FLOW_TAG as airbyte-to-flow
 
-FROM airbyte/source-amazon-ads:3.0.0
+FROM airbyte/source-amazon-ads:7.3.1
 
 COPY --from=airbyte-to-flow /airbyte-to-flow ./
 ENTRYPOINT ["/airbyte/integration_code/airbyte-to-flow", "--connector-entrypoint", "python /airbyte/integration_code/main.py"]