Fix inconsistent maven-javadoc-plugin version

Author: Isaac Brodsky

pom.xml

@@ -66,6 +66,7 @@
     <properties>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <org.openjdk.jmh.version>1.19</org.openjdk.jmh.version>
+        <maven.javadoc.plugin.version>3.1.1</maven.javadoc.plugin.version>
 
         <h3.git.remote>https://github.com/uber/h3.git</h3.git.remote>
         <h3.use.docker>true</h3.use.docker>
@@ -272,7 +273,7 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-javadoc-plugin</artifactId>
-                <version>3.1.1</version>
+                <version>${maven.javadoc.plugin.version}</version>
                 <executions>
                     <execution>
                         <id>attach-javadocs</id>
@@ -329,7 +330,7 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-javadoc-plugin</artifactId>
-                <version>3.0.0</version>
+                <version>${maven.javadoc.plugin.version}</version>
             </plugin>
             <plugin>
                 <groupId>org.codehaus.mojo</groupId>