Support for hash mode

Can this plugin support [hash mode](https://docs.simpleanalytics.com/hash-mode) please?

I suppose I'm expecting it to be an option for the plugin.

```js
plugins: [
  {
    resolve: "gatsby-plugin-simple-analytics",
    options: {
      mode: "hash",
    },
  },
]
```
If it's supported another way, I haven't been able to find it in the docs.

Simple Analytics is great by the way. Thanks.