various pom updates

Author: rbri

pom.xml

@@ -5,7 +5,7 @@
 
     <groupId>org.htmlunit</groupId>
     <artifactId>htmlunit-websocket-client</artifactId>
-    <version>3.12.0-SNAPSHOT</version>
+    <version>4.0.0-SNAPSHOT</version>
 
     <name>HtmlUnit WebSocket Client</name>
     <organization>
@@ -40,6 +40,29 @@
 
     <build>
         <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-enforcer-plugin</artifactId>
+                <version>3.4.1</version>
+                <executions>
+                    <execution>
+                        <id>enforce-maven</id>
+                        <goals>
+                            <goal>enforce</goal>
+                        </goals>
+                        <configuration>
+                            <rules>
+                                <requireMavenVersion>
+                                    <version>3.6.3</version>
+                                </requireMavenVersion>
+                                <requireJavaVersion>
+                                    <version>1.8.0</version>
+                                </requireJavaVersion>
+                            </rules>
+                        </configuration>
+                  </execution>
+                </executions>
+            </plugin>
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-jar-plugin</artifactId>
@@ -56,7 +79,7 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-shade-plugin</artifactId>
-                <version>3.5.1</version>
+                <version>3.5.2</version>
                 <executions>
                     <execution>
                         <phase>package</phase>
@@ -114,7 +137,7 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-javadoc-plugin</artifactId>
-                <version>3.6.0</version>
+                <version>3.6.3</version>
                 <configuration>
                     <quiet>true</quiet>
                     <!-- see https://stackoverflow.com/questions/69320220/maven-javadoc-listed-classes-twice -->
@@ -138,7 +161,7 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-gpg-plugin</artifactId>
-                <version>3.1.0</version>
+                <version>3.2.2</version>
                 <executions>
                     <execution>
                         <phase>verify</phase>