Add JSON Schema to list of projects (#845)

* Add JSON Schema to list of projects

* Update README.md

Use `HEAD` rather than `main` for link to JSON Schema Code of Conduct.

Co-authored-by: Jordan Harband <[email protected]>

Co-authored-by: Jordan Harband <[email protected]>

Author: Relequestual

README.md

@@ -67,6 +67,7 @@ The following projects are official OpenJS Foundation projects. If you are inter
 | | Project        | Charter           | Contributing       | Code of Conduct       |
 |-|----------------|:-----------------:|:------------------:|:---------------------:|
 | <img alt="logo of project ajv" src="https://github.com/openjs-foundation/artwork/raw/HEAD/projects/ajv/ajv-logo-color.svg" width="30" />  | [Ajv](https://ajv.js.org/) |   | [Contributing Guide](https://ajv.js.org/contributing) | [Code of Conduct](https://github.com/ajv-validator/ajv/blob/HEAD/CODE_OF_CONDUCT.md) |
+| <img alt="logo of project JSON Schema" src="https://github.com/openjs-foundation/artwork/raw/HEAD/projects/jsonschema/jsonschema-logo-color.svg" width="30" />  | [JSON Schema](https://json-schema.org/) |   | [Contributing Guide](https://github.com/json-schema-org/json-schema-spec/blob/draft-next/CONTRIBUTING.md) | [Code of Conduct](https://github.com/json-schema-org/.github/blob/HEAD/CODE_OF_CONDUCT.md) |
 | <img alt="logo of project LoopBack" src="https://github.com/openjs-foundation/artwork/raw/HEAD/projects/loopback/mark/blue/loopback.svg" width="30" /> | [LoopBack](https://loopback.io) |   | [Contributing Guide](https://github.com/loopbackio/loopback-next/blob/HEAD/docs/CONTRIBUTING.md) | [Code of Conduct](https://github.com/loopbackio/loopback-next/blob/HEAD/docs/CODE_OF_CONDUCT.md) |
 | <img alt="logo of project NativeScript" src="https://github.com/openjs-foundation/artwork/raw/HEAD/projects/nativescript/nativescript-icon-color.svg" width="30" /> | [NativeScript](https://nativescript.org/) |   | [Contributing Guide](https://github.com/NativeScript/NativeScript/blob/HEAD/tools/notes/CONTRIBUTING.md) | [Code of Conduct](https://github.com/NativeScript/codeofconduct) |