Fix hono adapter (#528)

* Fix undefined is not an object error in hono adapter

* Remove undefined header fallback for hono adaptor

* Use hono .json() api for responses

src/convenience/frameworks.ts

@@ -193,13 +193,12 @@ const hono: FrameworkAdapter = (ctx) => {
  let resolveResponse: (res: Response) => void;
  return {
  update: ctx.req.json(),
- header: ctx.req.headers.get(SECRET_HEADER) || undefined,
+ header: ctx.req.header(SECRET_HEADER),
  end: () => {
  resolveResponse(ctx.body());
  },
  respond: (json) => {
- ctx.header('Content-Type", "application/json');
- resolveResponse(ctx.body(json));
+ resolveResponse(ctx.json(json));
  },
  unauthorized: () => {
  ctx.status(401);