(doc) update plugins, skin

diff --git a/pom.xml b/pom.xml
index 4d49630..743f8f8 100644
--- a/pom.xml
+++ b/pom.xml
@@ -58,17 +58,37 @@
     <maven.version>3.1.1</maven.version>
     <javaVersion>7</javaVersion>
     <aether.version>0.9.0.M2</aether.version>
+    <surefire.version>2.22.2</surefire.version>
+    <checkstyle.violation.ignore>MethodLength</checkstyle.violation.ignore>
     <project.build.outputTimestamp>2021-01-23T01:12:59Z</project.build.outputTimestamp>
   </properties>
   
   <build>
     <pluginManagement>
       <plugins>
+        <!-- remove with parent-pom update -->
         <plugin>
           <groupId>org.apache.maven.plugins</groupId>
           <artifactId>maven-jxr-plugin</artifactId>
           <version>3.0.0</version>
         </plugin>
+        <plugin>
+          <artifactId>maven-enforcer-plugin</artifactId>
+          <version>3.0.0-M3</version>
+        </plugin>
+        <plugin>
+          <artifactId>maven-site-plugin</artifactId>
+          <version>3.9.1</version>
+        </plugin>
+        <plugin>
+          <artifactId>maven-project-info-reports-plugin</artifactId>
+          <version>3.1.1</version>
+        </plugin>
+        <plugin>
+          <groupId>org.apache.maven.plugins</groupId>
+          <artifactId>maven-javadoc-plugin</artifactId>
+          <version>3.2.0</version>
+        </plugin>
       </plugins>
     </pluginManagement>
   </build>
@@ -136,7 +156,7 @@
     <dependency>
       <groupId>junit</groupId>
       <artifactId>junit</artifactId>
-      <version>4.13.1</version>
+      <version>4.13.2</version>
       <scope>test</scope>
     </dependency>
     <dependency>
diff --git a/src/site/site.xml b/src/site/site.xml
index a18a2a6..1e3ab0b 100644
--- a/src/site/site.xml
+++ b/src/site/site.xml
@@ -19,7 +19,15 @@
 under the License.
 -->
 
-<project xmlns="http://maven.apache.org/DECORATION/1.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/DECORATION/1.0.0 http://maven.apache.org/xsd/decoration-1.0.0.xsd">
+<project xmlns="http://maven.apache.org/DECORATION/1.8.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/DECORATION/1.8.0 https://maven.apache.org/xsd/decoration-1.8.0.xsd">
+
+  <skin>
+    <groupId>org.apache.maven.skins</groupId>
+    <artifactId>maven-fluido-skin</artifactId>
+    <version>1.9</version>
+  </skin>
+
   <body>
     <menu name="Overview">
       <item name="Introduction" href="index.html"/>