Direct update from jdk17 to jdk21

Dockerfile

-FROM amazoncorretto:17.0.3-alpine as corretto-jdk
+FROM amazoncorretto:21-alpine as corretto-jdk
 
 ENV BASEDIR /data
 ENV TESTDIR $BASEDIR/test
@@ -11,7 +11,7 @@ RUN mkdir -p $TESTDIR \
     && mkdir $RESULTDIR \
     && mkdir -p /$LIBSDIR/additional
 
-ADD target/dta-jdk17-junit5-runner-jar-with-dependencies.jar /$BASEDIR/app.jar
+ADD target/dta-jdk21-junit5-runner-jar-with-dependencies.jar /$BASEDIR/app.jar
 ADD https://repo1.maven.org/maven2/org/junit/jupiter/junit-jupiter-api/5.10.0/junit-jupiter-api-5.10.0.jar /$LIBSDIR/
 ADD https://repo1.maven.org/maven2/org/junit/jupiter/junit-jupiter-engine/5.10.0/junit-jupiter-engine-5.10.0.jar /$LIBSDIR/
 ADD https://repo1.maven.org/maven2/org/junit/platform/junit-platform-engine/1.10.0/junit-platform-engine-1.10.0.jar /$LIBSDIR/

pom.xml

@@ -5,15 +5,15 @@
     <modelVersion>4.0.0</modelVersion>
 
     <groupId>de.hftstuttgart</groupId>
-    <artifactId>dta-jdk17-junit5-runner</artifactId>
+    <artifactId>dta-jdk21-junit5-runner</artifactId>
     <version>${env.BUILD_NUMBER}</version>
     <packaging>jar</packaging>
 
     <properties>
         <buildNumber>${env.BUILD_NUMBER}</buildNumber>
-        <java.version>17</java.version>
-        <maven.compiler.source>17</maven.compiler.source>
-        <maven.compiler.target>17</maven.compiler.target>
+        <java.version>21</java.version>
+        <maven.compiler.source>21</maven.compiler.source>
+        <maven.compiler.target>21</maven.compiler.target>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     </properties>