* ci(node): Move CI to Node 16 and add Node 18 to the matrix
* fix(netlify): Fix set-cookie not working on Node 18
* fix(netlify): Handle if `set-cookie` is already somehow an array (apparently it can?)
* test(node): Fix `toPromise` to match Astro's
* fix(tests): Use the actual underlying ArrayBuffer instance to create the buffer in toPromise
* chore: changeset
