chore(credential-provider-node): fix readme typo

[mxxk]

Description

The README of credential-provider-node currently refers to fromEnv (which does not exist in the package). This change fixes README to instead refer to defaultProvider.

Testing

N/A

Additional context

Since the initial introduction of packages/credential-provider-node/README.md in https://github.com/aws/aws-sdk-js-v3/commit/012558d471faf3ef80dd83628f81ba065c286e8a, the README referred to fromEnv, which did not exist then, nor does it exist now.

Later sections of README refer to the same factory function as defaultProvider:

https://github.com/aws/aws-sdk-js-v3/blob/65eb2e631383a82deb009bcb0983ae114c0c7b26/packages/credential-provider-node/README.md?plain=1#L65-L67

This change fixes the inconsistency.

Checklist

• [ ] If you wrote E2E tests, are they resilient to concurrent I/O?
• [ ] If adding new public functions, did you add the @public tag and enable doc generation on the package?

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[mxxk]

This is a very trivial PR which fixes a confusing typo in the README of a package, but it sat for 5 days without any activity. @jgrigg @kuhe @siddsriv @trivikr are you the right people to ping to get the ball rolling here?

[kuhe]

This is a welcome change. We have a large backlog and it may take a long time to get to individual PRs.

[mxxk]

Thank you for clarifying, reviewing, and merging @kuhe!