build(deps): update dependency org.apache.maven.plugins:maven-javadoc-plugin to v3.4.0 (googleapis#1636)

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This PR contains the following updates:

| Package | Change | Age | Adoption | Passing | Confidence |
|---|---|---|---|---|---|
| [org.apache.maven.plugins:maven-javadoc-plugin](https://maven.apache.org/plugins/) ([source](https://togithub.com/apache/maven-javadoc-plugin)) | `3.3.2` -> `3.4.0` | [![age](https://badges.renovateapi.com/packages/maven/org.apache.maven.plugins:maven-javadoc-plugin/3.4.0/age-slim)](https://docs.renovatebot.com/merge-confidence/) | [![adoption](https://badges.renovateapi.com/packages/maven/org.apache.maven.plugins:maven-javadoc-plugin/3.4.0/adoption-slim)](https://docs.renovatebot.com/merge-confidence/) | [![passing](https://badges.renovateapi.com/packages/maven/org.apache.maven.plugins:maven-javadoc-plugin/3.4.0/compatibility-slim/3.3.2)](https://docs.renovatebot.com/merge-confidence/) | [![confidence](https://badges.renovateapi.com/packages/maven/org.apache.maven.plugins:maven-javadoc-plugin/3.4.0/confidence-slim/3.3.2)](https://docs.renovatebot.com/merge-confidence/) |

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Author: renovate-bot

google-http-client-bom/pom.xml

@@ -128,7 +128,7 @@
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-javadoc-plugin</artifactId>
-        <version>3.3.2</version>
+        <version>3.4.0</version>
         <configuration>
           <skip>true</skip>
         </configuration>

pom.xml

@@ -302,7 +302,7 @@
         <plugin>
           <groupId>org.apache.maven.plugins</groupId>
           <artifactId>maven-javadoc-plugin</artifactId>
-          <version>3.3.2</version>
+          <version>3.4.0</version>
           <executions>
             <execution>
               <id>attach-javadocs</id>
@@ -702,7 +702,7 @@
           <plugin>
             <groupId>org.apache.maven.plugins</groupId>
             <artifactId>maven-javadoc-plugin</artifactId>
-            <version>3.3.2</version>
+            <version>3.4.0</version>
             <configuration>
               <doclet>com.microsoft.doclet.DocFxDoclet</doclet>
               <useStandardDocletOptions>false</useStandardDocletOptions>