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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)
```


payload={'n': event_publisher.get_hash(lambda_name)})
        arn = func_arn(lambda_name)
        if arn in region.lambdas:
            return error_response('Function already exist: %s' %
                lambda_name, 409, error_type='ResourceConflictException')
        region.lambdas[arn] = func_details = LambdaFunction(arn)
        func_details.versions = {VERSION_LATEST: {'RevisionId': str(uuid.uuid4())}}
        func_details.vpc_config = data.get('VpcConfig', {})
        func_details.last_modified = datetime.utcnow()
        func_details.description = data.get('Description', '')
        func_details.handler = data.get('Handler')
        func_details.runtime = data.get('Runtime')
        func_details.envvars = data.get('Environment', {}).get('Variables', {})
        func_details.tags = data.get('Tags', {})
        func_details.timeout = data.get('Timeout', LAMBDA_DEFAULT_TIMEOUT)
        func_details.role = data['Role']
        func_details.kms_key_arn = data.get('KMSKeyArn')
        func_details.memory_size = data.get('MemorySize')
        func_details.code_signing_config_arn = data.get('CodeSigningConfigArn')
        func_details.code = data['Code']
        func_details.package_type = data.get('PackageType') or 'Zip'
        func_details.image_config = data.get('ImageConfig', {})
        func_details.set_dead_letter_config(data)
        result = set_function_code(func_details.code, lambda_name)
        if isinstance(result, Response):
            del region.lambdas[arn]
            return result
        
        func_details.code.pop('ZipFile', None)