Upgrade to Servlet API 4.0.1.

We now build against a newer Servlet API version to align with Spring Framework.

Also, introduce a version property servlet.version for centralized version management.

Closes #1951

Author: mp911de

pom.xml

@@ -35,6 +35,7 @@
 		<springdata.solr>4.4.0-SNAPSHOT</springdata.solr>
 		<springdata.cassandra>3.2.0-SNAPSHOT</springdata.cassandra>
 		<springdata.keyvalue>2.5.0-SNAPSHOT</springdata.keyvalue>
+		<servlet.version>4.0.1</servlet.version>
 
 		<hibernate.version>5.4.8.Final</hibernate.version>
 		<jsonpath>1.1.0</jsonpath>

spring-data-rest-hal-explorer/pom.xml

@@ -35,7 +35,7 @@
 		<dependency>
 			<groupId>javax.servlet</groupId>
 			<artifactId>javax.servlet-api</artifactId>
-			<version>3.0.1</version>
+			<version>${servlet.version}</version>
 			<scope>provided</scope>
 		</dependency>
 

spring-data-rest-tests/pom.xml

@@ -32,7 +32,7 @@
 		<dependency>
 			<groupId>javax.servlet</groupId>
 			<artifactId>javax.servlet-api</artifactId>
-			<version>3.0.1</version>
+			<version>${servlet.version}</version>
 			<scope>provided</scope>
 		</dependency>
 

spring-data-rest-tests/spring-data-rest-tests-core/pom.xml

@@ -27,7 +27,7 @@
 		<dependency>
 			<groupId>javax.servlet</groupId>
 			<artifactId>javax.servlet-api</artifactId>
-			<version>3.0.1</version>
+			<version>${servlet.version}</version>
 			<scope>provided</scope>
 		</dependency>
 

spring-data-rest-webmvc/pom.xml

@@ -39,7 +39,7 @@
 		<dependency>
 			<groupId>javax.servlet</groupId>
 			<artifactId>javax.servlet-api</artifactId>
-			<version>3.0.1</version>
+			<version>${servlet.version}</version>
 			<scope>provided</scope>
 		</dependency>