The github.com/hashicorp/vault/sdk was listed in the replace section,
most likely because using a newer version failed. By adding a missing
tagged version to the `exclude` section in go.mod, updating the package
works fine.
Signed-off-by: Niels de Vos <ndevos@redhat.com>
Uses github.com/libopenstorage/secrets to communicate with Vault. This
removes the need for maintaining our own limited Vault APIs.
By adding the new dependency, several other packages got updated in the
process. Unused indirect dependencies have been removed from go.mod.
Signed-off-by: Niels de Vos <ndevos@redhat.com>