Increase task-runner memory limit

The task-runner is used to run rails console,
so it would occasionally require significant memory
to load the rails app.

scripts/review_apps/base-config.yaml

@@ -70,7 +70,7 @@ gitlab:
         memory: 800M
       limits:
         cpu: 450m
-        memory: 1200M
+        memory: 2000M
   webservice:
     resources:
       requests: