Update aws-sdk instructions for R2 api access

[pundang]

Existing documentation URL(s)

• https://developers.cloudflare.com/r2/examples/authenticate-r2-auth-tokens/

What changes are you suggesting?

This guide uses aws-sdk v2, which is currently in maintenance mode and nearing end of support (as mentioned here), you should upgrade to the new @aws-sdk/client-s3 package

Additional information

No response

[Oxyjun]

Hey @pundang , thanks for raising this issue! The linked PR will merge in the changes.

Thanks for contributing to Cloudflare docs! 😁