Increase "neutron-tempest-plugin-scenario-ovn" timeout to 3h

Due to a recent series of timeouts during the execution of this job,
this patch increases the timeout to 3h.

Change-Id: If0e9ea51ad62d4d324a77b9d33953b56d5e6c99c
Closes-Bug: #1949557
diff --git a/zuul.d/master_jobs.yaml b/zuul.d/master_jobs.yaml
index 68c7209..b167689 100644
--- a/zuul.d/master_jobs.yaml
+++ b/zuul.d/master_jobs.yaml
@@ -380,7 +380,7 @@
 - job:
     name: neutron-tempest-plugin-scenario-ovn
     parent: neutron-tempest-plugin-scenario
-    timeout: 10000
+    timeout: 10800
     vars:
       network_api_extensions: *api_extensions
       network_api_extensions_ovn: