Unrecognized token openapi

Description

I have problem with 3.1.x but 3.0.x works fine.

swagger.yaml

openapi: 3.1.0
info:
  description: test API
  title: test
  version: 1.0
servers:
  - url: /
tags:
  - name: examples-rest
    description: API examples
paths:
  /examples:
    get:
      tags:
        - examples-rest
      responses:
        '200':
          description: examples
          content:
            application/json:
              schema:
                type: array
                items:
                  $ref: '#/components/schemas/example'
components:
  schemas:
    example:
      type: object
      properties:
        reference:
          type: string
          maxLength: 18
        designation:
          type: string
          maxLength: 69

build.gradle

...
plugins {
    id 'org.springframework.boot' version '2.3.7.RELEASE'
    id 'io.spring.dependency-management' version '1.0.9.RELEASE'
    id 'java'
    id 'org.openapi.generator' version '5.1.1'
............
}

openApiGenerate {
    generatorName = "java"
    inputSpec = new File("$rootDir/swagger.yaml").toString()
    outputDir = new File("$buildDir/generated/openapi").toString()
    apiPackage = "com.example.controller"
    invokerPackage = "com.example"
    modelPackage = "com.example.model"
    modelNamePrefix = "Api"
    generateApiTests = false
    configOptions = [
            library            : "resttemplate",
            dateLibrary        : "java8-localdatetime",
            booleanGetterPrefix: "is",
            interfaceOnly      : "true"
    ]
}

sourceSets.main.java.srcDirs += "$buildDir/generated/openapi/src/main/java"

compileJava.dependsOn tasks.openApiGenerate

....
wrapper {
    gradleVersion = '6.4.1'
}

I have this error when I run gradlew.bat openApiGenerate

failed to read resource listing
com.fasterxml.jackson.core.JsonParseException: Unrecognized token 'openapi': was expecting (JSON String, Number, Array, Object or token 'null', 'true' or 'false')
 at [Source: (String)"openapi: 3.1.0
info:
  description: test API
  title: test
  version: 1.0
servers:
  - url: /
tags:
  - name: examples-rest
    description: API examples
paths:
  /example:
    get:
      tags:
        - example-rest
      responses:
 "[truncated 4489 chars]; line: 1, column: 8]
        at com.fasterxml.jackson.core.JsonParser._constructError(JsonParser.java:1851)
        at com.fasterxml.jackson.core.base.ParserMinimalBase._reportError(ParserMinimalBase.java:717)

There were issues with the specification. The option can be disabled via validateSpec (Maven/Gradle) or --skip-validate-spec (CLI).
   | Error count: 2, Warning count: 0
  Errors:
        -attribute openapi is unexpected
        -attribute paths.'/example'(get).responses.200.content is unexpected

Start with the supplied swagger.yaml and the openApiGenerate Gradle task, comparing the reported OpenAPI 3.1 behavior with the working 3.0.x case. Trace where the specification is parsed and validated, then verify that the 3.1 document is accepted and generation completes without the reported errors.