Remove usage of deprecated maven expressions

This commit replaces the usage of `${parent.version}`
with `${project.parent.version}` to fix the following
maven warning:

```
[WARNING] The expression ${parent.version} is deprecated.
Please use ${project.parent.version} instead.
```

Author: fmbenhassine

spring-batch-bom/pom.xml

@@ -46,22 +46,22 @@
 			<dependency>
 				<groupId>org.springframework.batch</groupId>
 				<artifactId>spring-batch-core</artifactId>
-				<version>${parent.version}</version>
+				<version>${project.parent.version}</version>
 			</dependency>
 			<dependency>
 				<groupId>org.springframework.batch</groupId>
 				<artifactId>spring-batch-infrastructure</artifactId>
-				<version>${parent.version}</version>
+				<version>${project.parent.version}</version>
 			</dependency>
 			<dependency>
 				<groupId>org.springframework.batch</groupId>
 				<artifactId>spring-batch-integration</artifactId>
-				<version>${parent.version}</version>
+				<version>${project.parent.version}</version>
 			</dependency>
 			<dependency>
 				<groupId>org.springframework.batch</groupId>
 				<artifactId>spring-batch-test</artifactId>
-				<version>${parent.version}</version>
+				<version>${project.parent.version}</version>
 			</dependency>
 		</dependencies>
 	</dependencyManagement>

spring-batch-core/pom.xml

@@ -23,7 +23,7 @@
 		<dependency>
 			<groupId>org.springframework.batch</groupId>
 			<artifactId>spring-batch-infrastructure</artifactId>
-			<version>${parent.version}</version>
+			<version>${project.parent.version}</version>
 		</dependency>
 		<dependency>
 			<groupId>org.springframework</groupId>

spring-batch-integration/pom.xml

@@ -22,7 +22,7 @@
 		<dependency>
 			<groupId>org.springframework.batch</groupId>
 			<artifactId>spring-batch-core</artifactId>
-			<version>${parent.version}</version>
+			<version>${project.parent.version}</version>
 		</dependency>
 		<dependency>
 			<groupId>org.springframework.integration</groupId>
@@ -65,7 +65,7 @@
 		<dependency>
 			<groupId>org.springframework.batch</groupId>
 			<artifactId>spring-batch-test</artifactId>
-			<version>${parent.version}</version>
+			<version>${project.parent.version}</version>
 			<scope>test</scope>
 		</dependency>
 		<dependency>

spring-batch-samples/pom.xml

@@ -20,7 +20,7 @@
 		<dependency>
 		  <groupId>org.springframework.batch</groupId>
 		  <artifactId>spring-batch-bom</artifactId>
-		  <version>${parent.version}</version>
+		  <version>${project.parent.version}</version>
 		  <type>pom</type>
 		  <scope>import</scope>
 		</dependency>

spring-batch-test/pom.xml

@@ -23,7 +23,7 @@
 		<dependency>
 			<groupId>org.springframework.batch</groupId>
 			<artifactId>spring-batch-core</artifactId>
-			<version>${parent.version}</version>
+			<version>${project.parent.version}</version>
 		</dependency>
 		<dependency>
 			<groupId>org.springframework</groupId>