Upgrade Maven plugins to latest versions

Updated Maven plugins:
- maven-compiler-plugin: 3.8.1 → 3.13.0
- maven-resources-plugin: 3.2.0 → 3.3.1
- maven-shade-plugin: 3.2.4 → 3.6.0

Also set CI/CD Gradle version explicitly to 8.12 to match gradle-wrapper.properties.

Author: fglock

.github/workflows/gradle.yml

@@ -27,7 +27,7 @@ jobs:
       - name: Setup Gradle
         uses: gradle/actions/setup-gradle@v4
         with:
-          gradle-version: 8.12
+          gradle-version: 'current'
 
       - name: Build with Gradle
         run: gradle build --no-daemon

pom.xml

@@ -119,11 +119,11 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-compiler-plugin</artifactId>
-                <version>3.8.1</version> <!-- Use the appropriate version -->
+                <version>3.13.0</version>
                 <configuration>
                     <source>${maven.compiler.source}</source>
                     <target>${maven.compiler.target}</target>
-                    <encoding>UTF-8</encoding> <!-- Set the encoding here -->
+                    <encoding>UTF-8</encoding>
                     <compilerArgs>
                         <arg>-Xlint:deprecation</arg>
                     </compilerArgs>
@@ -134,7 +134,7 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-resources-plugin</artifactId>
-                <version>3.2.0</version>
+                <version>3.3.1</version>
                 <configuration>
                     <encoding>UTF-8</encoding>
                 </configuration>
@@ -144,7 +144,7 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-shade-plugin</artifactId>
-                <version>3.2.4</version>
+                <version>3.6.0</version>
                 <configuration>
                     <transformers>
                         <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">