[JENKINS-23378] integrate Winstone 3.x that brings Servlet 3.1

executable-war module was also adjusted to keep up with the winstone
change.

war/pom.xml

@@ -49,7 +49,7 @@ THE SOFTWARE.
     <dependency>
       <groupId>org.jenkins-ci</groupId>
       <artifactId>executable-war</artifactId>
-      <version>1.30</version>
+      <version>1.33</version>
       <scope>provided</scope>
     </dependency>
     <dependency>
@@ -93,7 +93,7 @@ THE SOFTWARE.
       -->
       <groupId>org.jenkins-ci</groupId>
       <artifactId>winstone</artifactId>
-      <version>2.9</version>
+      <version>3.1</version>
       <scope>test</scope>
     </dependency>
     <dependency>