Update sheriff rotation URLs to rota-ng

Bug: 889221
Change-Id: Ie26aca388f600ee6a0983ee378c9b5b70e5efba6
Reviewed-on: https://chromium-review.googlesource.com/c/1342400Reviewed-by: John Budorick <jbudorick@chromium.org>
Commit-Queue: Ryan Tseng <hinoka@chromium.org>
Cr-Commit-Position: refs/heads/master@{#610125}

infra/config/global/luci-milo.cfg

@@ -4,51 +4,51 @@ headers {
   id: "chromium"
   oncalls {
     name: "Chromium"
-    url: "https://build.chromium.org/p/chromium/sheriff.json"
+    url: "https://rota-ng.appspot.com/legacy/sheriff.json"
   }
   oncalls {
     name: "Android"
-    url: "https://build.chromium.org/p/chromium/sheriff_android.json"
+    url: "https://rota-ng.appspot.com/legacy/sheriff_android.json"
   }
   oncalls {
     name: "iOS"
-    url: "https://build.chromium.org/p/chromium/sheriff_ios.json"
+    url: "https://rota-ng.appspot.com/legacy/sheriff_ios.json"
   }
   oncalls {
     name: "CrOS MTV"
-    url: "https://build.chromium.org/p/chromium/sheriff_cros_mtv.json"
+    url: "https://rota-ng.appspot.com/legacy/sheriff_cros_mtv.json"
   }
   oncalls {
     name: "CrOS non-MTV"
-    url: "https://build.chromium.org/p/chromium/sheriff_cros_nonmtv.json"
+    url: "https://rota-ng.appspot.com/legacy/sheriff_cros_nonmtv.json"
   }
   oncalls {
     name: "ChromeOS Gardener"
-    url: "https://build.chromium.org/p/chromium/sheriff_cr_cros_gardeners.json"
+    url: "https://rota-ng.appspot.com/legacy/sheriff_cr_cros_gardeners.json"
   }
   oncalls {
     name: "GPU"
-    url: "https://build.chromium.org/p/chromium/sheriff_gpu.json"
+    url: "https://rota-ng.appspot.com/legacy/sheriff_gpu.json"
   }
   oncalls {
     name: "Angle"
-    url: "https://build.chromium.org/p/chromium/sheriff_angle.json"
+    url: "https://rota-ng.appspot.com/legacy/sheriff_angle.json"
   }
   oncalls {
     name: "Perf"
-    url: "https://build.chromium.org/p/chromium/sheriff_perf.json"
+    url: "https://rota-ng.appspot.com/legacy/sheriff_perf.json"
   }
   oncalls {
     name: "Perfbot"
-    url: "https://build.chromium.org/p/chromium/sheriff_perfbot.json"
+    url: "https://rota-ng.appspot.com/legacy/sheriff_perfbot.json"
   }
   oncalls {
     name: "V8"
-    url: "https://build.chromium.org/p/chromium/sheriff_v8.json"
+    url: "https://rota-ng.appspot.com/legacy/sheriff_v8.json"
   }
   oncalls {
     name: "Trooper"
-    url: "https://build.chromium.org/p/chromium/trooper.json"
+    url: "https://rota-ng.appspot.com/legacy/trooper.json"
   }
   links {
     name: "Builds"
@@ -247,15 +247,15 @@ headers {
   id: "chromiumos"
   oncalls {
     name: "Sheriff"
-    url: "https://build.chromium.org/p/chromiumos/sheriff.json"
+    url: "https://rota-ng.appspot.com/legacy/sheriff.json"
   }
   oncalls {
     name: "Sheriff 2"
-    url: "https://build.chromium.org/p/chromiumos/sheriff2.json"
+    url: "https://rota-ng.appspot.com/legacy/sheriff2.json"
   }
   oncalls {
     name: "Gardeners"
-    url: "URL:https://build.chromium.org/p/chromiumos/sheriff_cr_cros_gardeners.js"
+    url: "https://rota-ng.appspot.com/legacy/sheriff_cr_cros_gardeners.json"
   }
   links {
     name: "Builds"