fix(aws-xray-sdk-fastify): add missing export default (#686)

* fix(aws-xray-sdk-fastify): add missing export default

* chore(aws-xray-sdk-fastify): update spaces

---------

Co-authored-by: Jorge Vargas <[email protected]>
Co-authored-by: Jonathan Lee <[email protected]>

Author: jorgevrgs

Diff for: sdk_contrib/fastify/lib/index.d.ts

@@ -1 +1,2 @@
 export * from './plugin';
+export { default } from './plugin';

Diff for: sdk_contrib/fastify/lib/plugin.js

@@ -16,3 +16,5 @@ const xRayFastifyPlugin = async (fastify, opts) => {
 };
 
 module.exports = xRayFastifyPlugin;
+
+exports.xRayFastifyPlugin = xRayFastifyPlugin;