[FLINK-38293] Update Checkstyle version and related rules in Kubernetes Operator

(cherry picked from commit acaa3e6)

Author: csviri

pom.xml

@@ -281,15 +281,7 @@ under the License.
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-checkstyle-plugin</artifactId>
-                <version>2.17</version>
-                <dependencies>
-                    <dependency>
-                        <groupId>com.puppycrawl.tools</groupId>
-                        <artifactId>checkstyle</artifactId>
-                        <!-- Note: match version with docs/flinkDev/ide_setup.md -->
-                        <version>8.14</version>
-                    </dependency>
-                </dependencies>
+                <version>3.6.0</version>
                 <executions>
                     <execution>
                         <id>validate</id>

tools/maven/checkstyle.xml

@@ -276,16 +276,9 @@ This file is based on the checkstyle file of Apache Beam.
 		<!-- Checks for Javadoc comments.                     -->
 		<!-- See http://checkstyle.sf.net/config_javadoc.html -->
 		<module name="JavadocMethod">
-			<property name="scope" value="protected"/>
 			<property name="severity" value="error"/>
-			<property name="allowMissingJavadoc" value="true"/>
 			<property name="allowMissingParamTags" value="true"/>
 			<property name="allowMissingReturnTag" value="true"/>
-			<property name="allowMissingThrowsTags" value="true"/>
-			<property name="allowThrowsTagsForSubclasses" value="true"/>
-			<property name="allowUndeclaredRTE" value="true"/>
-			<!-- This check sometimes failed for with "Unable to get class information for @throws tag" for custom exceptions -->
-			<property name="suppressLoadErrors" value="true"/>
 		</module>
 
 		<!-- Check that paragraph tags are used correctly in Javadoc. -->