Tweaks for the experimental SwarmBucket bot

infra/project-config/cr-buildbucket.cfg

 # Defines buckets on cr-buildbucket.appspot.com, used to schedule builds
 # on buildbot. In particular, CQ uses some of these buckets to schedule tryjobs.
 #
 # See http://luci-config.appspot.com/schemas/projects:buildbucket.cfg for
 # schema of this file and documentation.
 #
 # Please keep this list sorted by bucket name.
 
 buckets {
   name: "master.client.skia"
@@ skipping 77 matching lines @@
   swarming {
     hostname: "chromium-swarm.appspot.com"
     common_dimensions {
       key: "pool"
       value: "Skia"
     }
     common_swarming_tags: "master:master.client.skia.fyi"
     builders {
       name: "Build-Ubuntu-GCC-x86_64-Release-Swarmbucket"
       swarming_tags: "builder:Build-Ubuntu-GCC-x86_64-Release-Swarmbucket"
+      swarming_tags: "allow_milo:1"
       dimensions {
         key: "os"
         value: "Linux"
       }
+      dimensions {
+        key: "gpu"
+        value: "none"
+      }
       recipe {
-        repository: "https://chromium.googlesource.com/chromium/tools/build"
-        name: "skia/skia"
+        repository: "https://skia.googlesource.com/skia.git"
+        name: "swarm_trigger"
       }
     }
   }
 }