kong:2.8.4-alpine has removed linux/arm64 build

The `2.8.4-alpine` tag does not have an `linux/arm64` image currently. This image existed 2 weeks ago, but currently does not.

https://hub.docker.com/layers/library/kong/2.8.4-alpine/images/sha256-4252ac9254855225aeba185ab3cf7fa1891af5d37ab322cdeafa1527d323dfdf?context=explore

Additionally, `2.8.5` released recently, and there is no alpine variant of this version.

Start by checking the linked Docker Hub image details for Kong 2.8.4-alpine and the availability of the 2.8.5 alpine variant. Confirm whether linux/arm64 is missing and whether a repository change can restore or publish the requested images; done means both versions expose the expected alpine linux/arm64 image.

Written by the indexing model from the issue text.