Use new official artifact for jstl dep.

PiperOrigin-RevId: 727000866
Change-Id: I13859a4b5ea23b428a95c46ab37f03a3d08df691

Author: ludoch

applications/proberapp/pom.xml

@@ -51,7 +51,7 @@
             <artifactId>appengine-api-1.0-sdk</artifactId>
         </dependency>
         <dependency>
-            <groupId>jstl</groupId>
+            <groupId>javax.servlet</groupId>
             <artifactId>jstl</artifactId>
             <version>1.2</version>
         </dependency>