fix: Rename var AWS_SESSION_EXPIRATION for aws-vault v7+

[bruno]

In aws-vault v7.0.0 the authors removed the AWS_SESSION_EXPIRATION env var and recommend the use of AWS_CREDENTIAL_EXPIRATION. This commit just renames the variable name.

Description

A simple rename of the old ENV var that was expected to contain the expiration of the session to the new name.

Motivation and Context

As described in the commit message, aws-vault v7.0.0 no longer sets the variable named AWS_SESSION_EXPIRATION with the details of when the session will expire, so starship wasn't displaying it anymore.

Closes: #4783

I've run the cargo test locally on an Apple Silicon and x86 Linux (Ubuntu 22.04 LTS).

test result: ok. 951 passed; 0 failed; 32 ignored; 0 measured; 0 filtered out; finished in 0.82s

Screenshots (if appropriate):

How Has This Been Tested?

• I have tested using MacOS
• I have tested using Linux
• I have tested using Windows

Checklist:

• I have updated the documentation accordingly.
• I have updated the tests accordingly.

[davidkna]

I think adding support for the other environment variable is good, and it sounds like it should have a higher priority than the current value, but please keep the support of it for the time being. This new aws-vault release has only been out for 3 days, and other tools could using the variable.
Please also avoid making any changes to the non-English documentation.

[bruno]

Thanks for the feedback @davidkna. All good suggestions, sorry about the changes to the non-English docs. I will try to get to this in the near future ...