When creating the following bucket notification configuration:
```json
{
    "QueueConfigurations": [
        {
            "Id": "some-id",
            "QueueArn": "arn:aws:sqs:eu-central-1:123456789:my-queue",
            "Events": [
                "s3:ObjectCreated:*"
            ],
            "Filter": {
                "Key": {
                    "FilterRules": [
                        {
                            "Name": "Prefix",
                            "Value": "path/to/folder/"
                        },
                        {
                            "Name": "Suffix",
                            "Value": ".json"
                        }
                    ]
                }
            }
        }
    ]
}
```
and adding some files to S3, I get the following errors from localstack:

```
localstack.services.s3.s3_listener: Unknown filter name: "Prefix"
localstack.services.s3.s3_listener: Unknown filter name: "Suffix"
```

When I change the FilterRule names from "Prefix" to "prefix" and "Suffix" to "suffix", everything works. AWS supports the capitalised name, so this looks like a bug in localstack.
return {
        'DomainStatus': {
            'ARN': 'arn:aws:es:%s:%s:domain/%s' % (aws_stack.get_region(), TEST_AWS_ACCOUNT_ID, domain_name),
            'Created': True,
            'Deleted': deleted,
            'DomainId': '%s/%s' % (TEST_AWS_ACCOUNT_ID, domain_name),
            'DomainName': domain_name,
            'ElasticsearchClusterConfig': {
                'DedicatedMasterCount': 1,
                'DedicatedMasterEnabled': True,
                'DedicatedMasterType': 'm3.medium.elasticsearch',
                'InstanceCount': 1,
                'InstanceType': 'm3.medium.elasticsearch',
                'ZoneAwarenessEnabled': False
            },
            'ElasticsearchVersion': '6.7',
            'Endpoint': aws_stack.get_elasticsearch_endpoint(domain_name),
            'Processing': False,
            'EBSOptions': {
                'EBSEnabled': True,
                'VolumeType': 'gp2',
                'VolumeSize': 10,
                'Iops': 0
            },
        }
    }
@app.route('%s/domain' % API_PREFIX, methods=['GET'])
def list_domain_names():