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# Type of request: This is a ...

[x] bug report
[ ] feature request

# Detailed description
When I call the Lambda PutFunctionEventInvokeConfig API using the aws-java-sdk, the sdk throws an exception claiming it cannot parse the LastModified timestamp in the response:
```
software.amazon.awssdk.core.exception.SdkClientException: Unable to parse date : 2021-05-28T16:02:30.018Z
        at software.amazon.awssdk.core.exception.SdkClientException$BuilderImpl.build(SdkClientException.java:98)
        at software.amazon.awssdk.protocols.core.StringToInstant.lambda$safeParseDate$0(StringToInstant.java:77)
        at software.amazon.awssdk.protocols.core.StringToInstant.convert(StringToInstant.java:54)
        at software.amazon.awssdk.protocols.core.StringToInstant.convert(StringToInstant.java:32)
```

For comparison, the response for a getting a FunctionEventInvokeConfig for a Lambda of a real AWS account using the aws-cli is the following:
```
{
    "LastModified": "2021-05-27T19:26:43.454000-07:00",
    "FunctionArn": "...",
    ...
}
```

## Expected behavior
LambdaAsyncClient in aws-java-sdk should correctly parse the response for a PutFunctionEventInvokeConfig request.

## Actual behavior
LambdaAsyncClient in aws-java-sdk throws an exception when parsing the LastModified field in the response.

# Steps to reproduce

## Command used to start LocalStack
```
docker run -d --rm --name localstack -p 4566:4566 localstack/localstack:latest
```

## Client code (AWS SDK code snippet, or sequence of "awslocal" commands)
```
val putEventInvokeConfigRequest =
  PutFunctionEventInvokeConfigRequest.builder
    .functionName(functionName)
    .maximumEventAgeInSeconds(21600)
    .maximumRetryAttempts(0)
    .build
lambdaClient.putFunctionEventInvokeConfig(putEventInvokeConfigRequest)
```


'errorType': str(exc_type.__name__),
            'errorMessage': str(e),
            'stackTrace': traceback.format_tb(exc_traceback)
        }
        LOG.info('Error executing Lambda function %s: %s %s' % (func_arn, e, traceback.format_exc()))
        log_output = e.log_output if isinstance(e, lambda_executors.InvocationException) else ''
        return lambda_executors.InvocationResult(Response(json.dumps(response), status=500), log_output)
    finally:
        if suppress_output:
            sys.stdout = stdout_
            sys.stderr = stderr_
    return result
def exec_lambda_code(script, handler_function='handler', lambda_cwd=None, lambda_env=None):
    if lambda_cwd or lambda_env:
        EXEC_MUTEX.acquire()
        if lambda_cwd:
            previous_cwd = os.getcwd()
            os.chdir(lambda_cwd)
            sys.path = [lambda_cwd] + sys.path
        if lambda_env:
            previous_env = dict(os.environ)
            os.environ.update(lambda_env)
    
    lambda_id = 'l_%s' % short_uid()
    lambda_file = LAMBDA_SCRIPT_PATTERN.replace('*', lambda_id)
    save_file(lambda_file, script)
    
    TMP_FILES.append(lambda_file)
    TMP_FILES.append('%sc' % lambda_file)
    try: