Upgrade to java 21

Author: derTobsch

.github/workflows/build.yml

@@ -22,7 +22,7 @@ jobs:
         uses: actions/setup-java@v4
         with:
           distribution: 'temurin'
-          java-version: 17
+          java-version: 21
           cache: 'maven'
       - name: Build with Maven
         run: ./mvnw verify

.github/workflows/release.yml

@@ -13,11 +13,11 @@ jobs:
     runs-on: ubuntu-22.04
     steps:
       - uses: actions/checkout@v4
-      - name: Set up JDK 17
+      - name: Set up JDK
         uses: actions/setup-java@v4
         with:
           distribution: 'temurin'
-          java-version: 17
+          java-version: 21
           cache: 'maven'
           server-id: 'central'
           server-username: CENTRAL_USERNAME

pom.xml

@@ -53,8 +53,8 @@
 
     <properties>
         <revision>1.2.0-SNAPSHOT</revision>
-        <maven.compiler.source>17</maven.compiler.source>
-        <maven.compiler.target>17</maven.compiler.target>
+        <maven.compiler.source>21</maven.compiler.source>
+        <maven.compiler.target>21</maven.compiler.target>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     </properties>
 
@@ -172,12 +172,12 @@
                 <version>2.44.5</version>
                 <configuration>
                     <java>
-                        <googleJavaFormat />
-                        <importOrder />
-                        <removeUnusedImports />
-                        <formatAnnotations />
+                        <googleJavaFormat/>
+                        <importOrder/>
+                        <removeUnusedImports/>
+                        <formatAnnotations/>
                     </java>
-                    <pom />
+                    <pom/>
                 </configuration>
                 <executions>
                     <execution>