Update CTS media file download URL

Note: don't submit until URL is live

bug: 62088027
Test: run cts -m CtsMediaStressTestCases
Change-Id: I1473cecc3463a4b126b91cb14b6e8c82c01743df
diff --git a/tools/cts-tradefed/DynamicConfig.xml b/tools/cts-tradefed/DynamicConfig.xml
index 70d1a39..ffcf17c 100644
--- a/tools/cts-tradefed/DynamicConfig.xml
+++ b/tools/cts-tradefed/DynamicConfig.xml
@@ -15,6 +15,6 @@
 
 <dynamicConfig>
     <entry key="media_files_url">
-         <value>https://dl.google.com/dl/android/cts/android-cts-media-1.2.zip</value>
+         <value>https://dl.google.com/dl/android/cts/android-cts-media-1.3.zip</value>
     </entry>
 </dynamicConfig>