Clean up Region Resolver/Provider APIs

[epau]

Describe the feature

The APIs to resolve/provide a region are inconsistent with other similar constructs such as CredentialsProvider. We must clean up this API before going to GA to make it consistent with others.

Use Case

N/A

Proposed Solution

No response

Other Information

No response

Acknowledgements

• I may be able to implement this feature request
• This feature might incur a breaking change

[epau]

• Look at SEPs to verify structure and API design
• Make API consistent with other SDKs

[sichanyoo]

There does not exist any SEP or SRA section outlining the region resolver API as of 1/9/2024. There's nothing to verify against other than other SDKs. Checked Kotlin and Rust SDKs and there does not exist a consistency among region resolving APIs.

However, SRA does outline credentials provider (identity resolver) API, which uses method name getIdentity. Following this, region provider / resolver API will be changed from resolveRegion to getRegion for consistency.

[jbelkins]

Shipped in AWS SDK for Swift 0.34.0