disable_certificate_validation does not work in definitions

[filex]

My couper.hcl:

server "my-api" {
  api {
    endpoint "/**" {
      backend  = "foo"
    }
  }
}
definitions {
  backend "foo" {
    origin = "https://self-signed.badssl.com"
    disable_certificate_validation = true
  }
}

Although disable_certificate_validation is active, I get a request error:

$ http :8080/
…
{
    "error": {
        "code": 4002,
        "id": "c02mu9h8d3b4hja4foi0",
        "message": "API upstream connection error",
        "path": "/",
        "status": 502
    }
}

Couper's backend log says:

x509: certificate signed by unknown authority

However, the settings works, when defined in the endpoint:

server "my-api" {
  api {
    endpoint "/**" {
      backend {
        origin = "https://self-signed.badssl.com"
        disable_certificate_validation = true
      }
    }
  }
}

This config yields a 200, as expected.

[malud]

The issue here is the missing decode for hcl attributes which are not part of the related inline scheme and passing them to the desired options struct. Also the attribute test coverage must be increased along with a startup validation.