Fix: file name in "Example of setting dynamic environment URLs" example

What does this MR do and why?

This MR is to fix a typo. This will change the file name in the comment to the correct one (from dotenv to deploy.env)

Describe in detail what your merge request does and why.

Screenshots or screen recordings

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.