update runtime dependencies to sync Jetty and Pax Web versions

Use the same Pax Web and Jetty version for the runtime dependencies
(used by the demo application) as is used in the Karaf distribution.

This PR needs to be merged synchron to the updated bndrun in the openHAB
demo repository.

Related to: openhab#1197 (comment)

Signed-off-by: Markus Rathgeb <maggu2810@gmail.com>

bom/runtime/pom.xml

@@ -15,8 +15,8 @@
   <name>openHAB Core :: BOM :: Runtime</name>
 
   <properties>
-    <pax.web.version>7.2.3</pax.web.version>
-    <jetty.version>9.4.11.v20180605</jetty.version>
+    <pax.web.version>7.2.11</pax.web.version>
+    <jetty.version>9.4.20.v20190813</jetty.version>
   </properties>
 
   <dependencies>