[BUG] [Ada] Server skeleton does not compile when an operation has no parameter

Created by: stcarrez

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• Have you tested with the latest master to confirm the issue still exists?
• Have you searched for related issues/PRs?
• What's the actual output vs expected output?
• [Optional] Sponsorship to speed up the bug fix or feature request (example)

Description

When an operation definition consumes an application/json without specific parameter, the Ada skeleton that is generated does not compile.

The Ada skeleton is missing a use Swagger.Streams statement so it can be fixed by hand.

The Ada generated code also produces several compilation warnings that we can fix.

openapi-generator version

5.0 and 5.1

OpenAPI declaration file content or url

I put below an extract of such definition:

"put": {
  "operationId": "foo",
  "consumes": ["application/json"],
  "produces": ["application/json"],
  "responses": { ... }
}

Generation Details

Steps to reproduce

Related issues/PRs

Suggest a fix

I'll submit a pull request to fix this.