[release] v1.24.0 - Improved errors (#192)

Bug fixes:
- Errors for failed event logging not being sent to stderr or log
callback

Improvements:
- Introduced custom errors with matching: `ErrFailedLogEvent`
- Error messages in stderr now contain timestamps
- Network error messages include status code, # of retries, and endpoint
- Errors now sent to stderr instead of stdout





>Included In This Release
>- 42df398 kenny-statsig
>   - Nil-safe response status code check (#190)
>- 3c9f008 kenny-statsig
>   - improve error formatting (#188)
>- f53d35e kenny-statsig
>   - fix log event output error (#187)

statsig_metadata.go

@@ -14,7 +14,7 @@ type statsigMetadata struct {
 func getStatsigMetadata() statsigMetadata {
 	return statsigMetadata{
 		SDKType:         "go-sdk",
-		SDKVersion:      "1.23.0",
+		SDKVersion:      "v1.24.0",
 		LanguageVersion: runtime.Version()[2:],
 		SessionID:       SessionID(),
 	}