fix(read.me): #199 add Maven Wrapper, use ./mvnw is Readme uniformly, use java.version 18 in pom.xml uniformly,

Author: rainer-exxcellent

.mvn/wrapper/maven-wrapper.properties

@@ -0,0 +1,19 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+wrapperVersion=3.3.2
+distributionType=only-script
+distributionUrl=https://repo.maven.apache.org/maven2/org/apache/maven/apache-maven/3.9.9/apache-maven-3.9.9-bin.zip

README.md

@@ -42,7 +42,7 @@ only required to manage documents on the server or validate against the
 To build the application run:
 
 ```shell
-./mvn package
+./mvnw package
 ```
 
 The resulting jar file in the `target` folder can then be run with
@@ -179,12 +179,12 @@ When hostnames are changed, this has to adapted.
 
 ### build and execute tests
 
-./mvnw clean verify
+`` ./mvnw clean verify``
 
 
 ### start application
 
-./mvnw spring-boot:run
+`` ./mvnw spring-boot:run``
 
 with main class: de.bsi.secvisogram.csaf_cms_backend.SecvisogramApplication
 
@@ -222,10 +222,10 @@ You can find our guidelines here [CONTRIBUTING.md](https://github.com/secvisogra
 
 ### Check for Maven Plugin update
 
-`` mvn versions:display-plugin-updates `` 
+`` ./mvnw versions:display-plugin-updates `` 
 
 ## Check for dependency update
-`` mvn versions:display-dependency-updates `
+`` ./mvnw versions:display-dependency-updates ``
 
 ### Spring Boot