build(deps): update dependency org.apache.maven.plugins:maven-site-plugin to v3.12.1 (#1702)

[![Mend Renovate](https://app.renovatebot.com/images/banner.svg)](https://renovatebot.com)

This PR contains the following updates:

| Package | Change | Age | Adoption | Passing | Confidence |
|---|---|---|---|---|---|
| [org.apache.maven.plugins:maven-site-plugin](https://maven.apache.org/plugins/) ([source](https://github.com/apache/maven-site-plugin)) | `3.12.0` -> `3.12.1` | [![age](https://badges.renovateapi.com/packages/maven/org.apache.maven.plugins:maven-site-plugin/3.12.1/age-slim)](https://docs.renovatebot.com/merge-confidence/) | [![adoption](https://badges.renovateapi.com/packages/maven/org.apache.maven.plugins:maven-site-plugin/3.12.1/adoption-slim)](https://docs.renovatebot.com/merge-confidence/) | [![passing](https://badges.renovateapi.com/packages/maven/org.apache.maven.plugins:maven-site-plugin/3.12.1/compatibility-slim/3.12.0)](https://docs.renovatebot.com/merge-confidence/) | [![confidence](https://badges.renovateapi.com/packages/maven/org.apache.maven.plugins:maven-site-plugin/3.12.1/confidence-slim/3.12.0)](https://docs.renovatebot.com/merge-confidence/) |

---

### Configuration

📅 **Schedule**: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined).

🚦 **Automerge**: Disabled by config. Please merge this manually once you are satisfied.

♻ **Rebasing**: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox.

🔕 **Ignore**: Close this PR and you won't be reminded about this update again.

---

 - [ ] <!-- rebase-check -->If you want to rebase/retry this PR, click this checkbox.

---

This PR has been generated by [Mend Renovate](https://www.mend.io/free-developer-tools/renovate/). View repository job log [here](https://app.renovatebot.com/dashboard#github/googleapis/google-http-java-client).
<!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiIzMi4xNDMuMSIsInVwZGF0ZWRJblZlciI6IjMyLjE0My4xIn0=-->

Author: renovate-bot

google-http-client-bom/pom.xml

@@ -136,7 +136,7 @@
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-site-plugin</artifactId>
-        <version>3.12.0</version>
+        <version>3.12.1</version>
         <configuration>
           <skip>true</skip>
         </configuration>

pom.xml

@@ -360,7 +360,7 @@
         <plugin>
           <groupId>org.apache.maven.plugins</groupId>
           <artifactId>maven-site-plugin</artifactId>
-          <version>3.12.0</version>
+          <version>3.12.1</version>
         </plugin>
         <plugin>
           <groupId>org.apache.maven.plugins</groupId>