[release] v1.30.2 - Expose EvaluationSource, Init details for multi-client use (#243)

### Improvements
  - Make constants `EvaluationSource` and `EvaluationReason` public
- Expose `InitializeDetails` in new client initialize API
`NewClientWithDetatils` for multi-client use





>Included In This Release
>- 9134f9a kenny-statsig
>   - Make EvaluationSource and EvaluationReason values public (#242)
>- 571a6db kenny-statsig
>   - Add NewClientWithDetails API (#241)

Author: kenny-statsig

statsig_metadata.go

@@ -14,7 +14,7 @@ type statsigMetadata struct {
 func getStatsigMetadata() statsigMetadata {
 	return statsigMetadata{
 		SDKType:         "go-sdk",
-		SDKVersion:      "v1.30.1",
+		SDKVersion:      "v1.30.2",
 		LanguageVersion: runtime.Version()[2:],
 		SessionID:       SessionID(),
 	}