re-enable il2cpp builds (#73)

Author: Jamie Brynes

.buildkite/premerge.steps.yaml

@@ -67,15 +67,15 @@ steps:
       BUILD_ENVIRONMENT: "cloud"
       SCRIPTING_BACKEND: "mono"
 
-#  - label: "build UnityClient il2cpp"
-#    command: bash -c .shared-ci/scripts/build-worker.sh
-#    <<: *common
-#    artifact_paths:
-#      - logs/**/*
-#    env:
-#      WORKER_TYPE: "UnityClient"
-#      BUILD_ENVIRONMENT: "local"
-#      SCRIPTING_BACKEND: "il2cpp"
+  - label: "build UnityClient il2cpp"
+    command: bash -c .shared-ci/scripts/build-worker.sh
+    <<: *common
+    artifact_paths:
+      - logs/**/*
+    env:
+      WORKER_TYPE: "UnityClient"
+      BUILD_ENVIRONMENT: "local"
+      SCRIPTING_BACKEND: "il2cpp"
 
   - label: "build UnityGameLogic mono"
     command: bash -c .shared-ci/scripts/build-worker.sh