Add stubbed Package.swift

Package.swift

@@ -0,0 +1,33 @@
+// swift-tools-version:5.3
+
+// Copyright 2023 Google LLC
+//
+// 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.
+
+import PackageDescription
+
+let package = Package(
+  name: "abseil",
+  products: [
+    .library(name: "abseil", targets: ["abseil"])
+  ],
+  targets: [
+    .binaryTarget(
+      name: "abseil",
+      // TODO(ncooke3): Update the `url` with the actual value.
+      url: "URL_TO_BINARY",
+      // TODO(ncooke3): Update the `checksum` with the actual value.
+      checksum: "CHECKSUM"
+    )
+  ]
+)