Open redirect endpoint in Datasette

Datasette is an open source multi-tool for exploring and publishing data. In versions 0.65.1 and below and 1.0a0 through 1.0a19, deployed instances of Datasette include an open redirect vulnerability. Hits to the path //example.com/foo/bar/ (the trailing slash is required) will redirect the user to https://example.com/foo/bar. This problem has been patched in both Datasette 0.65.2 and 1.0a21. To workaround this issue, if Datasette is running behind a proxy, that proxy could be configured to replace // with / in incoming request URLs.