Add to repository the expected JSON schema of the attestation file

[yohhaan]

I would suggest adding to this repository the expected schema of the JSON attestation file.

Here is the schema I came up with:

{
    "type": "object",
    "properties": {
        "privacy_sandbox_api_attestations": {
            "type": "array",
            "items": {
                "type": "object",
                "properties": {
                    "attestation_parser_version": {
                        "type": "string"
                    },
                    "attestation_version": {
                        "type": "string"
                    },
                    "privacy_policy": {
                        "type": "array",
                        "items": {
                            "type": "string"
                        }
                    },
                    "ownership_token": {
                        "type": "string"
                    },
                    "issued_seconds_since_epoch": {
                        "type": "number"
                    },
                    "expiry_seconds_since_epoch": {
                        "type": "number"
                    },
                    "enrollment_id": {
                        "type": "string"
                    },
                    "platform_attestations": {
                        "type": "array",
                        "items": {
                            "type": "object",
                            "properties": {
                                "platform": {
                                    "type": "string"
                                },
                                "attestations": {
                                    "type": "object",
                                    "attribution_reporting_api": {
                                        "type": "object",
                                        "properties": {
                                            "ServiceNotUsedForIdentifyingUserAcrossSites": {
                                                "type": "boolean"
                                            }
                                        },
                                        "required": [
                                            "ServiceNotUsedForIdentifyingUserAcrossSites"
                                        ]
                                    },
                                    "topics_api": {
                                        "type": "object",
                                        "properties": {
                                            "ServiceNotUsedForIdentifyingUserAcrossSites": {
                                                "type": "boolean"
                                            }
                                        },
                                        "required": [
                                            "ServiceNotUsedForIdentifyingUserAcrossSites"
                                        ]
                                    },
                                    "protected_audience_api": {
                                        "type": "object",
                                        "properties": {
                                            "ServiceNotUsedForIdentifyingUserAcrossSites": {
                                                "type": "boolean"
                                            }
                                        },
                                        "required": [
                                            "ServiceNotUsedForIdentifyingUserAcrossSites"
                                        ]
                                    },
                                    "shared_storage_api": {
                                        "type": "object",
                                        "properties": {
                                            "ServiceNotUsedForIdentifyingUserAcrossSites": {
                                                "type": "boolean"
                                            }
                                        },
                                        "required": [
                                            "ServiceNotUsedForIdentifyingUserAcrossSites"
                                        ]
                                    },
                                    "private_aggregation_api": {
                                        "type": "object",
                                        "properties": {
                                            "ServiceNotUsedForIdentifyingUserAcrossSites": {
                                                "type": "boolean"
                                            }
                                        },
                                        "required": [
                                            "ServiceNotUsedForIdentifyingUserAcrossSites"
                                        ]
                                    }
                                }
                            },
                            "required": [
                                "platform",
                                "attestations"
                            ]
                        }
                    }
                },
                "required": [
                    "attestation_parser_version",
                    "attestation_version",
                    "privacy_policy",
                    "ownership_token",
                    "issued_seconds_since_epoch",
                    "enrollment_id",
                    "platform_attestations"
                ]
            }
        }
    },
    "required": [
        "privacy_sandbox_api_attestations"
    ]
}