Manually revert back pqcrypto-internals to 0.2.5

Darwin runners fail after the update of this crate
which is a transient dependency. Using `[patch]` doesn't
update properly so this is a manual attempt.

There's outstanding PR which claims to fix the issue:
rustpq/pqcrypto#72

The error in question from compilation:
```
cargo:warning=<instantiation>:79:5: error: instruction requires: sha3
```

Signed-off-by: Lukas Pukenis <[email protected]>