Prepare release 1.17

[edmorley]

To pick up #149.

[edmorley]

https://github.com/heroku/heroku-buildpack-nginx/releases/tag/v1.17

$ heroku buildpacks:publish heroku-community/nginx v1.17
Publishing buildpack heroku-community/nginx... done
Publishing buildpack was successful

$ heroku buildpacks:versions heroku-community/nginx | head -n 4
 Version Released At              Status
 ─────── ──────────────────────── ─────────
 19      2026-04-14T09:05:50.759Z published
 18      2026-02-26T11:15:41.126Z published