Bump org.apache.maven.plugins:maven-javadoc-plugin from 2.9.1 to 3.6.3

Bumps [org.apache.maven.plugins:maven-javadoc-plugin](https://github.com/apache/maven-javadoc-plugin) from 2.9.1 to 3.6.3.
- [Release notes](https://github.com/apache/maven-javadoc-plugin/releases)
- [Commits](apache/maven-javadoc-plugin@maven-javadoc-plugin-2.9.1...maven-javadoc-plugin-3.6.3)

---
updated-dependencies:
- dependency-name: org.apache.maven.plugins:maven-javadoc-plugin
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

pom.xml

@@ -184,7 +184,7 @@
                     <plugin>
                         <groupId>org.apache.maven.plugins</groupId>
                         <artifactId>maven-javadoc-plugin</artifactId>
-                        <version>2.9.1</version>
+                        <version>3.6.3</version>
                         <executions>
                             <execution>
                                 <id>attach-javadocs</id>