kong:2.8.4-alpine has removed linux/arm64 build

[jaxtonw]

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.