Migration maven->gradle, openapi plugin replacement

I tried to migrate some projects from maven to gradle with great performance improvements. But I still have some issues, the main blocker is, that i cannot find a replacement for the following plugins
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  	<plugin>
  		<groupId>org.codehaus.mojo</groupId>
  		<artifactId>build-helper-maven-plugin</artifactId>
  		<executions>
  			<execution>
  				<phase>generate-sources</phase>
  				<goals>
  					<goal>add-source</goal>
  				</goals>
  				<configuration>
  					<sources>
  						<source>${project.build.directory}/generated-sources/openapi/src/main/java</source>
  						<source>${project.build.directory}/generated-sources/openapi/src/main/resources</source>
  					</sources>
  				</configuration>
  			</execution>
  		</executions>
  	</plugin>
  	<plugin>
  		<groupId>org.openapitools</groupId>
  		<artifactId>openapi-generator-maven-plugin</artifactId>
  		<version>3.3.4</version>
  		<executions>
  			<execution>
  				<goals>
  					<goal>generate</goal>
  				</goals>
  			</execution>
  		</executions>
  		<configuration>
  			<inputSpec>${project.basedir}/../NM_Rest_API_Definition.yaml</inputSpec>
  			<apiPackage>iview.nm.api</apiPackage>
  			<modelPackage>iview.nm.api</modelPackage>
  			<invokerPackage>iview.nm.invoker</invokerPackage>

  			<generatorName>spring</generatorName>
  			<library>spring-boot</library>
  			<dateLibrary>java8</dateLibrary>
  			<configHelp>false</configHelp>
  			<configOptions>
  				<interfaceOnly>true</interfaceOnly>
  			</configOptions>
  			<interfaceOnly>true</interfaceOnly>
  		</configuration>
  	</plugin>
  <plugins>

I should generate the support code for OpenAPI-based REST APIs from a yaml file. I am using Gradle 6.0.1 and am new to Gradle. Has anyone already had this problem? Could you help me with the solution?