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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)
```


LOG.debug(msg)
    return aws_responses.flask_error_response_json(msg, code=code, error_type=error_type)
def get_zip_bytes(function_code):
    """Returns the ZIP file contents from a FunctionCode dict.
    :type function_code: dict
    :param function_code: https://docs.aws.amazon.com/lambda/latest/dg/API_FunctionCode.html
    :returns: bytes of the Zip file.
    """
    function_code = function_code or {}
    if 'S3Bucket' in function_code:
        s3_client = aws_stack.connect_to_service('s3')
        bytes_io = BytesIO()
        try:
            s3_client.download_fileobj(function_code['S3Bucket'], function_code['S3Key'], bytes_io)
            zip_file_content = bytes_io.getvalue()
        except Exception as e:
            raise ClientError('Unable to fetch Lambda archive from S3: %s' % e, 404)
    elif 'ZipFile' in function_code:
        zip_file_content = function_code['ZipFile']
        zip_file_content = base64.b64decode(zip_file_content)
    elif 'ImageUri' in function_code:
        zip_file_content = None
    else:
        raise ClientError('No valid Lambda archive specified: %s' % list(function_code.keys()))
    return zip_file_content
def get_java_handler(zip_file_content, main_file, func_details=None):
    """Creates a Java handler from an uploaded ZIP or JAR.
    :type zip_file_content: bytes
    :param zip_file_content: ZIP file bytes.
    :type handler: str