docs: fix incorrect information in README.md

[axolo]

What type of PR is this?

pref: Update .env file path in README

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• This PR title match the format: <type>(optional scope): <description>
• The description of this PR title is user-oriented and clear enough for others to understand.
• Add documentation if the current PR requires user awareness at the usage level.

[CLAassistant]

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[fanlv]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.You have signed the CLA already but the status is still pending? Let us recheck it.

@axolo cla 签一下。