How to get Swagger UI to show required fields from DTO for POST RequestBody

Question

I have the following DTO which uses the @Parameter annotation to mark the first field as "required":

import io.swagger.v3.oas.annotations.Parameter;
import io.swagger.v3.oas.annotations.media.Schema;

import javax.validation.constraints.NotNull;

@Schema(description = "My DTO")
class VectorFoo {
  // The below attribute is required
  @NotNull
  @Parameter(description = "my first attribute", required = true)
  private String attribute1;

  // The below attribute is optional
  @Parameter(description = "my second attribute", required  = false)
  private String attribute2;

  public String getAttribute1() {
    return attribute1;
  }

  public void setAttribute1(String attribute1) {
    this.attribute1 = attribute1;
  }

  public String getAttribute2() {
    return attribute2;
  }

  public void setAttribute2(String attribute2) {
    this.attribute2 = attribute2;
  }
}

And the following REST Endpoint code:

  @PostMapping("/fstVector")
  public ResponseEntity<VectorFoo> fstVPost(
      // RequestBody objects are "required" by default. To make them optional, add "(required = false)"
      @org.springframework.web.bind.annotation.RequestBody   // Spring
      @io.swagger.v3.oas.annotations.parameters.RequestBody  // Swagger
      @Valid // Bean validation to ensure if the incoming object is valid
      final VectorFoo v1
  ) {
    return new ResponseEntity<>(v1, HttpStatus.OK);
  }

Which produces the following Swagger UI. Note the lack of "required" notation on on any of the fields the Request Body section.

I understand from this StackOverflow post that this should have worked to show "required" in the Swagger UI for the Request Body example (see final answer with Swagger UI Screenshots): Post about Swagger UI and "required" fields in RequestBody

Can anyone help me understand how I can get Swagger to show the required fields that have been marked as "required" (on the DTO with the @Parameter annotation) in the Request Body documentation on the Swagger UI?

Thanks.