Can't use gpg because there's no gpg package in Alpine 3.14

[onlookor]

As title.
The current docker official vault image is ver 1.11.3, based on Alpine 3.14. There's no offical gpg package in Alpine 3.14, so it's hard to use GPG in vault.
Alpine provides gpg packages since version 3.15, its' better to update the base image as soon as possible.