Conan-center-index: [service] cairo is not available

[Croydon]

Just an issue so that this is not getting lost

https://github.com/conan-io/conan-center-index/pull/2847#issuecomment-727255681

// @ericLemanissier @jgsogo @danimtb

[jgsogo]

Cairo is ready! https://conan.io/center/cairo

We've prepared a new job (https://github.com/conan-io/conan-center-index/pull/3598) that will run in the background and will take care of these issues.

[ericLemanissier]

Thank you !!