add 'AWS_REGION' to output when formatting credentials output

[AlexVulaj]

What type of PR is this?

feature

What this PR does / Why we need it?

When outputting cloud credentials with the -o env flag, the current output will contain the region as AWS_DEFAULT_REGION. Looking at the AWS docs, this seems to be dropping in favor of AWS_REGION. Furthermore, some AWS SDKs don't even acknowledge the AWS_DEFAULT_REGION envar.

Resolves OSD-23927

[rafael-azevedo]

/lgtm

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 44.58%. Comparing base (a8a9d8a) to head (33fdf6e).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #443   +/-   ##
=======================================
  Coverage   44.58%   44.58%           
=======================================
  Files          63       63           
  Lines        5291     5291           
=======================================
  Hits         2359     2359           
  Misses       2615     2615           
  Partials      317      317           

Files	Coverage Δ
pkg/credentials/aws.go	16.66% <100.00%> (ø)

[openshift-ci]

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[hectorakemp]

/lgtm
/approve

[openshift-ci]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: AlexVulaj, hectorakemp, rafael-azevedo

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