JSON Schemas generated by API Platform should include additionalProperties: false

[quentinus95]

API Platform version(s) affected: 2.5.1

Description
Today, JSON Schemas generated by API-Platform do not include additionalProperties: false. This reduces type saftey when using a code generator.

How to reproduce
Create an ApiResource in a new project, check the generated Swagger documentation. The JSON Schema generated for the ApiResource does not include additionalProperties: false.

Possible Solution
Simply add additionalProperties: false when generating the schema.

[teohhanhui]

Feel free to open a PR targeting master. 😄

[quentinus95]

@teohhanhui here you go: #3388

[soyuka]

#3804

[soyuka]

Will be out in the next release