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.
Refer to branch tip commit hash in srcurl

Rather than referring to a branch in `srcurl`, refer to the commit hash
for the tip of that branch.

Also, bump the package version accordingly so that Launchpad will accept
this new package.