refactor(router): remove error handlers from the router

This allows to use multiple openapi middlewares for the same app.

BREAKING CHANGE: Error handling must be confgured outside of the middleware.

src/index.ts

@@ -45,13 +45,5 @@ export const createMockMiddleware = ({
     return res.locals.operation ? res.locals.operation.generateResponse(req, res) : next();
   });
 
-  router.use((req, res) => {
-    res.status(404).send({ message: 'Not found' });
-  });
-
-  router.use((err: Error, req: express.Request, res: express.Response): void => {
-    res.status(500).send({ message: 'Something broke!' });
-  });
-
   return router;
 };

test/integration.spec.ts

@@ -45,13 +45,6 @@ describe('middleware', () => {
     expect(typeof response.body.name).toBe('string');
   });
 
-  it('should return an 404 error response if the given url does not exist', async () => {
-    const response = await request.get('/api/pet-not-exist/2');
-
-    expect(response.status).toBe(404);
-    expect(response.body).toHaveProperty('message', 'Not found');
-  });
-
   it('should return an 400 error response if request body is not valid', async () => {
     const response = await request
       .post('/api/pet')