Main readme example doesn't work with Oak current#17

Hi, thanks for making this, it seems cool (and the Bedrock team selected it, so it must be good)! I'm a not-so-good JS developer, but am experimenting with this. I tried to use the Readme example with Deno, and got this error: ``` c@macmini ~/D/r/oak_sessions> deno run ./foo.ts Check file:///Users/c/Documents/react/oak_sessions/foo.ts error: TS2345 [ERROR]: Argument of type '(ctx: Context, next: () => Promise<unknown>) => Promise<void>' is not assignable to parameter of type 'Middleware<State, Context<State, AppState>>'. Types of parameters 'ctx' and 'context' are incompatible. Type 'Context<State, AppState>' is not assignable to type 'Context<State, Record<string, any>>'. Types of property 'app' are incompatible. Type 'Application<AppState>' is not assignable to type 'Application<Record<string, any>>'. Property '#contextState' in type 'Application' refers to a different member that cannot be accessed from within type 'Application'. app.use(session.initMiddleware()) ~~~~~~~~~~~~~~~~~~~~~~~~ at file:///Users/c/Documents/react/oak_sessions/foo.ts:19:9 ``` I had no idea what to do with that error. Luckily, I found one of the Oak versions this was authored with in the file 'deps.ts' By modifing the Readme example to use the same Oak version, the Readme example runs fine. Maybe you want to change the Readme to include the Oak version, so it works for others out of the box? Anyway, thanks for making & sharing this!