Fix Maven version in description of Java Maven stack (#441)

https://catalog.redhat.com/software/containers/ubi9/openjdk-17/61ee7c26ed74b2ffb22b07f6?image=65a90783d59cca758b7d8d64&container-tabs=packages
https://catalog.redhat.com/software/containers/ubi8/openjdk-11/5dd6a4b45a13461646f677f4?image=6639ed26fe2c35406921c084&container-tabs=packages

Signed-off-by: Aurélien Pupier <apupier@redhat.com>

Author: apupier

stacks/java-maven/1.2.0/devfile.yaml

@@ -2,7 +2,7 @@ schemaVersion: 2.1.0
 metadata:
   name: java-maven
   displayName: Maven Java
-  description: Java application based on Maven 3.6 and OpenJDK 11
+  description: Java application based on Maven 3.8 and OpenJDK 11
   icon: https://raw.githubusercontent.com/devfile-samples/devfile-stack-icons/main/java-maven.jpg
   tags:
     - Java

stacks/java-maven/1.3.0/devfile.yaml

@@ -2,7 +2,7 @@ schemaVersion: 2.1.0
 metadata:
   name: java-maven
   displayName: Maven Java
-  description: Java application based on Maven 3.6 and OpenJDK 17
+  description: Java application based on Maven 3.8 and OpenJDK 17
   icon: https://raw.githubusercontent.com/devfile-samples/devfile-stack-icons/main/java-maven.jpg
   tags:
     - Java

stacks/java-maven/1.3.1/devfile.yaml

@@ -2,7 +2,7 @@ schemaVersion: 2.2.2
 metadata:
   name: java-maven
   displayName: Maven Java
-  description: Java application based on Maven 3.6 and OpenJDK 17
+  description: Java application based on Maven 3.8 and OpenJDK 17
   icon: https://raw.githubusercontent.com/devfile-samples/devfile-stack-icons/main/java-maven.jpg
   tags:
     - Java