Disable all jobs for testing

Change-Id: Ib87a9ffe99a6a39265521d6c1a6cc4cf68181274
diff --git a/mbed-tls-pr-merge.yaml b/mbed-tls-pr-merge.yaml
index 14dc9c2..789eb47 100644
--- a/mbed-tls-pr-merge.yaml
+++ b/mbed-tls-pr-merge.yaml
@@ -2,7 +2,7 @@
     name: mbed-tls-pr-merge
     description: 'Job for testing PRs merged with the target branch head'
     project-type: multibranch
-    disabled: false
+    disabled: true
     prune-dead-branches: true
     days-to-keep: 60
     num-to-keep: 1000