JMeter Plugins does not support empty libs

[Baraujo25]

When a plugin does not require libs to be published to JMeter plugins the jmeter-plugin-publish-action generates:

 "1.0.0": {
        "changes": "Some changes",
        "downloadUrl": "https://download-plugin-url.com",
        "libs": {}
  }

Which ends up failing drastically in jmeter-plugins repository:

Uncaught Exception net.sf.json.JSONException: JSONObject["libs"] is not a JSONObject. in thread Thread[AWT-EventQueue-0,6,main]. See log file for details.
Uncaught Exception net.sf.json.JSONException: JSONObject["libs"] is not a JSONObject. in thread Thread[AWT-EventQueue-0,6,main]. See log file for details.
Uncaught Exception net.sf.json.JSONException: JSONObject["libs"] is not a JSONObject. in thread Thread[AWT-EventQueue-0,6,main]. See log file for details.
Uncaught Exception net.sf.json.JSONException: JSONObject["libs"] is not a JSONObject. in thread Thread[AWT-EventQueue-0,6,main]. See log file for details.
Uncaught Exception net.sf.json.JSONException: JSONObject["libs"] is not a JSONObject. in thread Thread[AWT-EventQueue-0,6,main]. See log file for details.
Uncaught Exception net.sf.json.JSONException: JSONObject["libs"] is not a JSONObject. in thread Thread[AWT-EventQueue-0,6,main]. See log file for details.

The expected release object generated for above example should be:

 "1.0.0": {
        "changes": "Some changes",
        "downloadUrl": "https://download-plugin-url.com",
  }

Considerations

• Verify emptiness of all fields when release object gets created, since this issue could also happen in multiple fields due to lack of validations on jmeter-plugins side.

Issue proof

• This release was done using jmeter-plugin-publish-action generating above issue. Resulting in this manual pull request for hot-fixing.