As reported on Discord, the changes in #3446 do not always properly parse the value of the Cache-Control header, causing the server to fail to start. For example, the response returned by Google Cloud IAM includes a header of the shape

cache-control: public, max-age=18341, must-revalidate, no-transform

and this is rejected by graphql-engine on startup, causing it to exit with the following somewhat unhelpful message:

Failed parsing Cache-Control header from JWK response. Could not find max-age or s-maxage

It would be nice if we could use some existing, off-the-shelf parser to parse this information, not roll our own.