fix: return correct exit code on interrupt

[kirilyuro]

Description

Changed entry script to return status code 130, instead of 0, on KeyboardInterrupt.

Related Issue

#244

Motivation and Context

When used in other scripts that rely on gimme-aws-creds, this will enable to distinguish between the credentials being acquired successfully vs gimme-aws-creds being interrupted without actually acquiring the credentials.

How Has This Been Tested?

Made this change locally in my /usr/local/bin/gimme-aws-creds (macOS), saw that this now returns the correct status when interrupted.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.