Broken link to index.js for lambda-udfs/f_upper_nodejs

Hello,

Seems like you have a broken link to nodejs upper functionality. I was trying to figure out how to write a udf in GO and trying to find reference in NodeJS as I am more familiar on it. There seems to be couple of things missing/incomplete

1. The comments are referring to Python in this directory. See line 3 on file function.sql
> This sample function demonstrates how to create/use lambda UDFs in python
2. index.js file is missing.
3. I believe the docs was referring that package.json is needed but I don't see it

So can someone add the index.js on there? I would be happy to send a PR too for this

Start in the lambda-udfs/f_upper_nodejs directory by reading function.sql and checking the referenced Node.js sample files. Confirm the expected package.json and index.js structure from nearby UDF examples, then update the broken reference and Python comment; done means the link resolves and the sample is complete and consistent with its documentation.

Written by the indexing model from the issue text.