Add TrunkStable.bp

All the branches except udc-mainline-prod have TrunkStable.bp.
So this CL adds this file to avoid conflicts.
TrunkStable.bp is not included by Android.bp in udc-mainline-prod.
So, this CL is a no-op.

AOSP-first: TrunkStable.bp exists in aosp
Test: TH
Merged-In: Ib69d2fdc1d73b36a08a3d8ae1f2c45b2bcffae64

Change-Id: Ib3fe0774086ab5531f0e4d776da23667d32daad4
diff --git a/common/TrunkStable.bp b/common/TrunkStable.bp
new file mode 100644
index 0000000..772f79e
--- /dev/null
+++ b/common/TrunkStable.bp
@@ -0,0 +1,21 @@
+//
+// Copyright (C) 2023 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+aconfig_declarations {
+    name: "com.android.net.flags-aconfig",
+    package: "com.android.net.flags",
+    srcs: ["flags.aconfig"],
+}