Update minimum memlimit for policy.rs to fix runtime error

[unullmass]

Resolves #161.

use std::collections::HashMap;
use wasmtime::{Config, Engine, Module, Store};
use opa_wasm::Runtime;
use anyhow::Result;


#[tokio::main]
async fn main() -> Result<()> {
    // Configure the WASM runtime
    let mut config = Config::new();
    config.async_support(true);

    let engine = Engine::new(&config)?;

    // Load the policy WASM module
    let module = opa_wasm::read_bundle("bundle.tar.gz").await?;
    let module:Module = Module::new(&engine, module)?;

    // Create a store which will hold the module instance

    let mut store = Store::new(&engine, ());


    let data = HashMap::from([("hello", "world")]);
    let input = HashMap::from([("message", "world")]);

    // Instantiate the module
    let runtime = Runtime::new(&mut store, &module).await?;

    let policy = runtime.with_data(&mut store, &data).await?;

    // Evaluate the policy
    let res: serde_json::Value = policy.evaluate(&mut store, "hello/world", &input).await?;

    println!("{}", res);

    Ok(())
}

Able to see the evaluation result now for this code:

Error: could not find entrypoint hello/world

[sandhose]

Whilst I don't see any harm with upping the minimum memory linked with the module (other that it will allocate one potentially unused 64k page by default), I'm not sure I see the point of enabling memory64 support? OPA's WASM module won't use it, and the memory type allocated to it is not in 64bit mode either?

[unullmass]

@sandhose I have removed the code pertaining to 64-bit memory from the above example.

[sandhose]

Sure, but then what is this PR fixing exactly? The example should work without this PR, right?