bad zip in go-example-lambda-runtime-api-proxy-extension

The zip file produced [here](https://github.com/aws-samples/aws-lambda-extensions/tree/2f7d61e8e66df99eb5fa733ff23bd25ce18b6d26/go-example-lambda-runtime-api-proxy-extension#building-the-package-and-dependencies) and [here](https://github.com/aws-samples/aws-lambda-extensions/blob/2f7d61e8e66df99eb5fa733ff23bd25ce18b6d26/go-example-lambda-runtime-api-proxy-extension/Makefile) includes the `ARTIFACTS_DIR` in the zip making it invalid and the extension does not run.

You're probably missing the zip `-j` flag.

Start with the package-building instructions and the Makefile in go-example-lambda-runtime-api-proxy-extension, focusing on the command that creates the zip. Verify the archive layout after building it. Done means the zip does not include ARTIFACTS_DIR and the extension runs as intended.

Written by the indexing model from the issue text.