golang-github-tink-crypto-tink-go-hcvault release 2.4.0-2 for unstable

[dgit distro=debian split --quilt=unapplied]
[dgit please-upload source=golang-github-tink-crypto-tink-go-hcvault version=2.4.0-2 upstream-tag=v2.4.0 upstream=78c5aea1900e732f6b10688b70b0560197050407]