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.
config_status = get_domain_config_status()
    return {
        'DomainConfig': {
            'AccessPolicies': {
                'Options': '{"Version":"2012-10-17","Statement":[{"Effect":"Allow","Principal":{"AWS":"arn:aws:iam::%s:root"},"Action":"es:*","Resource":"arn:aws:es:%s:%s:domain/%s/*"}]}' % (TEST_AWS_ACCOUNT_ID, aws_stack.get_region(), TEST_AWS_ACCOUNT_ID, domain_name),  
                'Status': config_status
            },
            'AdvancedOptions': {
                'Options': {
                    'indices.fielddata.cache.size': '',
                    'rest.action.multi.allow_explicit_index': 'true'
                },
                'Status': config_status
            },
            'EBSOptions': {
                'Options': {
                    'EBSEnabled': True,
                    'EncryptionEnabled': False,
                    'Iops': 0,
                    'VolumeSize': 10,
                    'VolumeType': 'gp2'
                },
                'Status': config_status