S3 Autoconfiguration supports DefaultCredentialProvider.

[Akayeshmantha]

:loudspeaker: Type of change

• [] Bugfix
• [ ] New feature
• [X] Enhancement
• [ ] Refactoring

:scroll: Description

S3 AutoConfiguration AutoConfigures Credential Provider.

:bulb: Motivation and Context

https://github.com/awspring/spring-cloud-aws/issues/1385

:green_heart: How did you test it?

:pencil: Checklist

• [X] I reviewed submitted code
• [X] I added tests to verify changes
• [ ] I updated reference documentation to reflect the change
• [X] All tests passing
• [X] No breaking changes

:crystal_ball: Next steps

[maciejwalkowiak]

Can we make the test first reproduce the issue?