Wagyu build fails
Hi @howardwu,

When trying to run `cargo install wagyu` I'm hit with the following:

```
    Updating crates.io index
  Downloaded wagyu v0.6.3
  Downloaded 1 crate (48.9 KB) in 0.48s
  Installing wagyu v0.6.3
error: failed to compile `wagyu v0.6.3`, intermediate artifacts can be found at `/run/user/1000/cargo-installoftX6F`

Caused by:
  failed to select a version for the requirement `aes = "^0.2"`
  candidate versions found which didn't match: 0.8.2, 0.8.1, 0.8.0, ...
  location searched: crates.io index
  required by package `wagyu-zcash v0.6.3`
      ... which satisfies dependency `wagyu-zcash = "^0.6.3"` of package `wagyu v0.6.3`
```

Not sure if I'm doing something wrong or the app needs some update.