Upgrade to Maven Javadoc Plugin 2.10.4

Closes gh-6274

Author: wilkinsona

spring-boot-dependencies/pom.xml

@@ -2092,7 +2092,7 @@
 				<plugin>
 					<groupId>org.apache.maven.plugins</groupId>
 					<artifactId>maven-javadoc-plugin</artifactId>
-					<version>2.10.1</version>
+					<version>2.10.4</version>
 				</plugin>
 				<plugin>
 					<groupId>org.apache.maven.plugins</groupId>