Update dependencies and build for Java 20

Verified that new major Guava version does not introduce any incompatible changes:
https://github.com/google/guava/releases/tag/v32.0.0
Dependant projects should be updated to use these newer versions of Guava and Kryo.

Author: abyrd

pom.xml

@@ -55,20 +55,20 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-compiler-plugin</artifactId>
-                <version>3.8.1</version>
+                <version>3.11.0</version>
                 <configuration>
                     <!-- Target Java LTS 11 -->
-                    <release>11</release>
+                    <release>20</release>
                 </configuration>
             </plugin>
             <plugin>
                 <artifactId>maven-surefire-plugin</artifactId>
-                <version>3.0.0-M8</version>
+                <version>3.1.2</version>
             </plugin>
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-jar-plugin</artifactId>
-                <version>3.1.2</version>
+                <version>3.3.0</version>
                 <configuration>
                     <archive>
                         <manifestEntries>
@@ -84,7 +84,7 @@
                 <!-- Recommended way to deploy to OSSRH -->
                 <groupId>org.sonatype.plugins</groupId>
                 <artifactId>nexus-staging-maven-plugin</artifactId>
-                <version>1.6.12</version>
+                <version>1.6.13</version>
                 <extensions>true</extensions>
                 <configuration>
                     <serverId>ossrh</serverId>
@@ -98,7 +98,7 @@
                 <!-- Allow attaching Javadoc during releases -->
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-javadoc-plugin</artifactId>
-                <version>3.1.1</version>
+                <version>3.5.0</version>
                 <configuration>
                     <!-- Turn off strict Javadoc checking -->
                     <doclint>none</doclint>
@@ -130,7 +130,7 @@
                 <!-- Include zipped source code in releases -->
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-source-plugin</artifactId>
-                <version>3.0.1</version>
+                <version>3.3.0</version>
                 <executions>
                     <execution>
                         <id>attach-sources</id>
@@ -144,7 +144,7 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-gpg-plugin</artifactId>
-                <version>1.5</version>
+                <version>3.1.0</version>
                 <executions>
                     <execution>
                         <id>sign-artifacts</id>
@@ -167,7 +167,7 @@
             <dependency>
                 <groupId>org.junit</groupId>
                 <artifactId>junit-bom</artifactId>
-                <version>5.9.2</version>
+                <version>5.10.0</version>
                 <type>pom</type>
                 <scope>import</scope>
             </dependency>
@@ -179,7 +179,7 @@
         <dependency>
             <groupId>com.esotericsoftware</groupId>
             <artifactId>kryo</artifactId>
-            <version>5.4.0</version>
+            <version>5.5.0</version>
         </dependency>
 
         <!-- Trove provides optimized map/set collections for primitive types (int, long, etc.) -->
@@ -194,19 +194,19 @@
         <dependency>
             <groupId>com.google.guava</groupId>
             <artifactId>guava</artifactId>
-            <version>31.1-jre</version>
+            <version>32.1.2-jre</version>
         </dependency>
         <!-- Logging API. -->
         <dependency>
             <groupId>org.slf4j</groupId>
             <artifactId>slf4j-api</artifactId>
-            <version>2.0.6</version>
+            <version>2.0.7</version>
         </dependency>
         <!-- Logging API implementation. -->
         <dependency>
             <groupId>ch.qos.logback</groupId>
             <artifactId>logback-classic</artifactId>
-            <version>1.4.5</version>
+            <version>1.4.11</version>
         </dependency>
         <!-- Junit is for unit testing. -->
         <dependency>