Trigger workflows for v1.3 stable branch

Now that were getting a new v1.3 branch thats probably going to stick around for a while, we should enable the nightly runs for it as well similarly to how we've done it for v1.2 in the past (e.g update and uncomment the following line)

https://github.com/duckdb/duckdb-workflow-trigger/blob/a3101abb11af4293fb0f2ed32c0fc9f6784f57ba/.github/workflows/Workflow-Trigger.yml#L30C8-L30C55