Build jsps to Java 17 bytecode

As the webapp is already at Java 17 there is no point in targetting
older bytecode for jsps.

Author: akurtakov

ua/org.eclipse.help.webapp/pom.xml

@@ -38,8 +38,8 @@
               </jspc>
               <webAppSourceDirectory>${basedir}</webAppSourceDirectory>
               <useProvidedScope>true</useProvidedScope>
-              <sourceVersion>11</sourceVersion>
-              <targetVersion>11</targetVersion>
+              <sourceVersion>17</sourceVersion>
+              <targetVersion>17</targetVersion>
             </configuration>
           </execution>
         </executions>