Update enviroments.md - example CURL requests had a typo in the URL

What does this MR do?

This MR fixes typo's in 2 example CURL commands. The request URL's were missing the "s" in "environments".

Are there points in the code the reviewer needs to double check?

This error may be present in other places in the documentation?

Why was this MR needed?

Running the CURL commands returned an error.