docs: mention that the minimum `role-duration-seconds` is `900`

[nitrocode]

Describe the issue

By default, the value is set to 3600 seconds.
Valid Range: Minimum value of 900. Maximum value of 43200.

https://docs.aws.amazon.com/STS/latest/APIReference/API_AssumeRoleWithSAML.html

---

It would be nice to document this in the README so it's clear.

[lehmanmj]

Thanks for the suggestion :) we have made this change.

[github-actions]

Comments on closed issues are hard for our team to see.
If you need more assistance, please either tag a team member or open a new issue that references this one.