cargo test -F der: cannot find macro `vec` in this scope

[kpcyrd]

hello!

while updating the Debian package to crypto-bigint 0.7.5 I noticed the following test failure in our automated test suite:

error: cannot find macro `vec` in this scope
   --> src/uint/encoding/der.rs:244:23
    |
244 |         let mut der = vec![0x02, 17, 0x01];
    |                       ^^^

error: could not compile `crypto-bigint` (lib test) due to 1 previous error

Steps to reproduce are "cargo test with the der feature enabled".

Thanks!

[kpcyrd]

Fixed in #1323 :)