Add headers to API GW proxy response.

Author: dealako

core/response.go

@@ -85,10 +85,17 @@ func (r *ProxyResponseWriter) GetProxyResponse() (events.APIGatewayProxyResponse
 		isBase64 = true
 	}
 
+	proxyHeaders := make(map[string]string, len(r.headers))
+
+	for h := range r.headers {
+		proxyHeaders[h] = r.headers.Get(h)
+	}
+
 	return events.APIGatewayProxyResponse{
 		StatusCode:        r.status,
 		MultiValueHeaders: http.Header(r.headers),
 		Body:              output,
 		IsBase64Encoded:   isBase64,
+		Headers:           proxyHeaders,
 	}, nil
 }