Upgrade to Maven Wrapper 3.8.3.

See #1250

Author: mp911de

.mvn/wrapper/maven-wrapper.properties

@@ -1,2 +1,2 @@
-#Fri Sep 10 15:38:05 CEST 2021
-distributionUrl=https\://repo.maven.apache.org/maven2/org/apache/maven/apache-maven/3.8.2/apache-maven-3.8.2-bin.zip
+#Mon Oct 11 14:30:33 CEST 2021
+distributionUrl=https\://repo.maven.apache.org/maven2/org/apache/maven/apache-maven/3.8.3/apache-maven-3.8.3-bin.zip