Make spring-jdbc a required dependency in core

As of v4, spring-jdbc was optional since
Spring Batch provided a Map-based job
repository.

In v5, the Map-based job repository has
been removed and the only option now is
the Jdbc-based implementation which requires
spring-jdbc.

Resolves #4048
Related to #3836

Author: fmbenhassine

spring-batch-core/pom.xml

@@ -45,6 +45,11 @@
 			<artifactId>spring-tx</artifactId>
 			<version>${spring-framework.version}</version>
 		</dependency>
+		<dependency>
+			<groupId>org.springframework</groupId>
+			<artifactId>spring-jdbc</artifactId>
+			<version>${spring-framework.version}</version>
+		</dependency>
 		<dependency>
 			<groupId>com.fasterxml.jackson.core</groupId>
 			<artifactId>jackson-databind</artifactId>
@@ -75,12 +80,6 @@
 			<version>${aspectj.version}</version>
 			<optional>true</optional>
 		</dependency>
-		<dependency>
-			<groupId>org.springframework</groupId>
-			<artifactId>spring-jdbc</artifactId>
-			<version>${spring-framework.version}</version>
-			<optional>true</optional>
-		</dependency>
 
 		<!-- test dependencies -->
 		<dependency>