Upgrade schemas to the latest draft version 2020-12

[decentralgabe]

The schemas should all be updated to support the most recent json schema version. There are tools to automate this work.

[mistermoe]

only concern here is other languages not yet supporting 2020-12

[decentralgabe]

Libs we use by language:

• Kotlin - https://github.com/networknt/json-schema-validator supports v2020-12
• JS - couldn't find one that we use but https://github.com/ajv-validator/ajv supports v2020-12
• Swift - not using one yet but https://github.com/kylef/JSONSchema.swift supports v2020-12
• Go - https://github.com/santhosh-tekuri/jsonschema supports v2020-12

[decentralgabe]

I have successfully used https://github.com/sourcemeta/alterschema to convert between versions

[mistermoe]

i started with v2020-12 but had revert to v7 because the kotlin lib's implementation differs from the js one 😭