Bump maven version to 3.9.6 to match mavenResolverVersion 1.9.18

Resolve resolution conflict exceptions where 3.9.4 of maven depends on 1.9.14 of mavenResolverVersion. Sync'ing the mavenVersion to 3.9.6 with the declared mavenResolveVersion 1.9.18 eliminates the version conflict. 

see: https://github.com/apache/maven/blob/maven-3.9.6/pom.xml

Signed-off-by: Bryan Kelly <[email protected]>

Author: xyloman

spring-boot-testjars-maven/build.gradle

@@ -10,7 +10,7 @@ group = 'org.springframework.experimental.boot'
 
 ext {
 	mavenResolverVersion = '1.9.18'
-	mavenVersion = '3.9.4'
+	mavenVersion = '3.9.6'
 }
 
 java {