Field `url` is required for type with serial name `com.saveourtool.osv4k.Reference`, but it was missing

Occurs when uploading certain OSV JSON files (needs to be forwarded to saveourtool/cosv4k).

Examples:

• CAN-2022-1000071
• CAN-2023-1000000

18:02:10.937 [boundedElastic-187] ERROR c.s.cosv.backend.service.CosvService - Failed to process raw COSV file with id: 15467 kotlinx.serialization.MissingFieldException: Field 'url' is required for type with serial name 'com.saveourtool.osv4k.Reference', but it was missing
	at kotlinx.serialization.internal.PluginExceptionsKt.throwMissingFieldException(PluginExceptions.kt:20)
	at com.saveourtool.osv4k.Reference.<init>(OsvSchema.kt:890)
	at com.saveourtool.osv4k.Reference$$serializer.deserialize(OsvSchema.kt:890)
	at com.saveourtool.osv4k.Reference$$serializer.deserialize(OsvSchema.kt:890)
	at kotlinx.serialization.json.internal.PolymorphicKt.decodeSerializableValuePolymorphic(Polymorphic.kt:77)

This seems like a rather frequent error, so we need to either replace the missing url field with a dummy value, or fix this in saveourtool/cosv4k and upgrade: