title: Context is empty in GraphQL middleware
body: <p>I'm sending from frontend authorization token in headers and then I want to check validity of this token in some endpoints using middleware and context, but context is always empty.</p>
  <p>I'm using type-graphql.</p>
  <p>Frontend code (I check request in 'Network' tab and I can see my additional header):</p>
  <pre><code>  private async mutate&lt;T&gt;(
      mutation: DocumentNode,
      data: unknown,
      token?: string
    ) {
      const response = await apolloClient.mutate&lt;T&gt;({
        mutation: mutation,
        context: {
          headers: {
            'auth-token': token || '',
          },
        },
        variables: {
          data: data,
        },
      });
      return response.data;
    }
  </code></pre>
  <p>Resolver code:</p>
  <pre><code> @Mutation(() =&gt; Token)
    @UseMiddleware(authMiddleware)
    async login(@Ctx() ctx: unknown, @Arg('data') data: LoginInput) {
      console.log(ctx);
     ...
    }
  </code></pre>
  <p>Middleware code:</p>
  <pre><code>export const authMiddleware: MiddlewareFn = ({ context }, next) =&gt; {
    console.log(context);
    try {
      return next();
    } catch (error) {
      return next();
    }
  };
  </code></pre>
  <p>console.log is always equal to <code>{}</code></p>