Custom middleware in keyless-plugin-api.json does not work

[Lanchez]

Driver definition in keyless-plugin-api.json is at wrong place and the middleware does not work.

https://github.com/TykTechnologies/tyk-gateway-docker/blob/e44c765f4aca9aad2a80309c5249ff46b308e46e/apps/keyless-plugin-api.json#L28

This should be under custom_middleware object like this:

    "custom_middleware": {
        "pre": [
            {
                "name": "testJSVMData",
                "path": "./middleware/injectHeader.js",
                "require_session": false,
                "raw_body_only": false
            }
        ],
        "driver": "otto"
    }