Bump vault version to 1.16.3, the latest community release:
https://github.com/hashicorp/vault/blob/main/CHANGELOG.md#1163

This adds the variable S3_EXPIRE_DAYS.

The idea of this feature is to allow the script to prune expired
snapshot files on the S3 compatible remote storage. Files are considered
expired once they exceed the threshold defined by S3_EXPIRE_DAYS.

This feature is usefull for S3 compatible storage where there exist no
lifecycle rules to clean up the storage of expired or old files, such
as:
* cloudscale object storage
* Exoscale simple object storage (SOS)

It is recommended to also configure a "Governance" lock on the files, to
ensure no files are deleted by accident before the defined
S3_EXPIRE_DAYS threshold.

The date manipulation did not work in my tests with busybox on
OpenShift.

This should work even in the busybox environments. It simply subtracts
seconds.