Upgrade to Maven Wrapper 3.9.3.

See #1775

Author: mp911de

.mvn/wrapper/maven-wrapper.properties

@@ -1,2 +1,2 @@
-#Tue Jun 13 08:55:13 CEST 2023
-distributionUrl=https\://repo.maven.apache.org/maven2/org/apache/maven/apache-maven/3.9.2/apache-maven-3.9.2-bin.zip
+#Mon Jul 03 09:49:54 CEST 2023
+distributionUrl=https\://repo.maven.apache.org/maven2/org/apache/maven/apache-maven/3.9.3/apache-maven-3.9.3-bin.zip