Make build work with jdk 11/17

- Fixes #326

spring-shell-dependencies/pom.xml

@@ -9,7 +9,6 @@
 		<artifactId>spring-shell-parent</artifactId>
 		<groupId>org.springframework.shell</groupId>
 		<version>3.0.0-SNAPSHOT</version>
-		<relativePath />
 	</parent>
 
 	<dependencyManagement>

spring-shell-docs/pom.xml

@@ -173,7 +173,6 @@
 			<plugin>
 				<groupId>org.apache.maven.plugins</groupId>
 				<artifactId>maven-javadoc-plugin</artifactId>
-				<version>3.3.1</version>
 				<executions>
 					<execution>
 						<id>dependency-javadocs</id>
@@ -192,13 +191,6 @@
 							</dependencySourceExcludes>
 							<quiet>true</quiet>
 							<attach>false</attach>
-							<links>
-								<link>
-									https://docs.spring.io/spring-framework/docs/current/javadoc-api/
-								</link>
-								<link>http://jcommander.org/apidocs/</link>
-								<link>https://docs.spring.io/spring-shell/docs/1.2.0.RELEASE/api/</link>
-							</links>
 							<doclint>-missing</doclint>
 						</configuration>
 					</execution>