Title: Expired SSL cert on mirror - external dependency - kafka

Description:

The download mirror for the kafka dependency seems to have an expired certificate and from-source builds are not currently possible with an empty bazel cache.

There may not actually be any resolution to this from the Envoy project's side, but creating the ticket for posterity and to note for the maintainers.

Error from browser when attemping to access the Kafka download:

Repro steps:

bazelisk clean --expunge
bazelisk build //...