Downgrade minijinja to 0.30.2

```
error[E0432]: unresolved import `std::sync::atomic::AtomicU64`
   --> /home/runner/.cargo/registry/src/index.crates.io-6f17d22bba15001f/minijinja-0.30.3/src/value/mod.rs:111:43
    |
111 | use std::sync::atomic::{self, AtomicBool, AtomicU64};
    |                                           ^^^^^^^^^
    |                                           |
    |                                           no `AtomicU64` in `sync::atomic`
    |                                           help: a similar name exists in the module: `AtomicU8`

```