[#80633966] Release ruby-hiera-eyaml-gpg (0.4-5-gb10d8a8)

Using the fork at:
https://github.com/alphagov/hiera-eyaml-gpg/tree/avoid_gpghome_env_var

This includes a change to set the GPG home directory without using the
GPGHOME environment variable.

* * *

Supersedes #75; this PR adds d6ea556 following @alext's feedback.