datasette-export-database 0.3a1 patches CSRF cookie breakage from Datasette 1.0a27

Simon Willison shipped a point release of his datasette-export-database plugin to repair a regression introduced by Datasette 1.0a27. The plugin had been relying on the ds_csrftoken cookie to construct a custom signed URL, but the upstream release stopped setting that cookie, breaking the export flow.

The 0.3a1 update swaps in a replacement signing mechanism so the plugin works again under the latest Datasette alpha. It is a maintenance release driven entirely by upstream churn rather than new functionality, and serves as a reminder that plugins riding pre-1.0 Datasette internals should expect to chase breaking changes through the alpha series.