Add additional properties to OpenApiConfig

[msosnicki]

Background

• The JsonSchemaMapper and OpenApiMapper have access to OpenApiConfig. In some cases (see related smithy4s PR), there is a need to pass additional information to such mappers. This PR adds Map<String, String> additionalProperties field to enable that

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By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[kubukoz]

suggestion: shall we have a method to just put into the properties, without having to pass the entire map?

i.e. void putAdditionalProperty(String key, String value)

[kubukoz]

also, looks like ModelAssembler allows Object values so maybe we should be as flexible here as well. String is fairly limiting, after all.

[msosnicki]

Yeah, makes sense, changed so it resembles how it's done in ModelAssembler

[kstich]

Is the behavior you're looking for already filled by the JsonSchemaConfig.getExtensions(YourCustomConfig.class) method? That will populate additional fields into the YourCustomConfig class from on content that was unknown to the underlying JsonSchemaConfig when loaded.

[msosnicki]

Is the behavior you're looking for already filled by the JsonSchemaConfig.getExtensions(YourCustomConfig.class) method? That will populate additional fields into the YourCustomConfig class from on content that was unknown to the underlying JsonSchemaConfig when loaded.

Sorry for late reply, the extension mechanism is exactly what is needed, thanks!