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.
result = {
        'DomainNames': [{'DomainName': name} for name in ES_DOMAINS.keys()]
    }
    return jsonify(result)
@app.route('%s/es/domain' % API_PREFIX, methods=['POST'])
def create_domain():
    data = json.loads(to_str(request.data))
    domain_name = data['DomainName']
    if domain_name in ES_DOMAINS:
        return error_response(error_type='ResourceAlreadyExistsException')
    ES_DOMAINS[domain_name] = data
    result = get_domain_status(domain_name)
    
    event_publisher.fire_event(event_publisher.EVENT_ES_CREATE_DOMAIN,
        payload={'n': event_publisher.get_hash(domain_name)})
    return jsonify(result)
@app.route('%s/es/domain/<domain_name>' % API_PREFIX, methods=['GET'])
def describe_domain(domain_name):
    if domain_name not in ES_DOMAINS:
        return error_response(error_type='ResourceNotFoundException')
    result = get_domain_status(domain_name)
    return jsonify(result)
@app.route('%s/es/domain/<domain_name>/config' % API_PREFIX, methods=['GET', 'POST'])
def domain_config(domain_name):
    config = get_domain_config(domain_name)
    return jsonify(config)
@app.route('%s/es/domain/<domain_name>' % API_PREFIX, methods=['DELETE'])
def delete_domain(domain_name):