Update build to resolve dependencies from maven central first

Author: fmbenhassine

build.gradle

@@ -37,10 +37,10 @@ allprojects {
 	group = 'org.springframework.batch'
 
 	repositories {
+		mavenCentral()
 		maven { url 'https://repo.spring.io/libs-snapshot' }
 		maven { url 'https://repo.spring.io/libs-milestone' }
 		maven { url 'https://repo.spring.io/plugins-release' }
-		mavenCentral()
 	}
 
 	ext {