Build failure on 32-bit platforms

[valpackett]

From this i386 log:

error[E0308]: mismatched types
   --> acme_common/src/crypto/openssl_certificate.rs:111:39
    |
111 |         let now = Asn1Time::from_unix(timestamp)?;
    |                                       ^^^^^^^^^ expected `i32`, found `i64`
    |
help: you can convert an `i64` to `i32` and panic if the converted value wouldn't fit
    |
111 |         let now = Asn1Time::from_unix(timestamp.try_into().unwrap())?;
    |                                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Maybe the timestamp should not hardcode i64..

[breard-r]

Thank you for reporting it!