fix(shared): include an actual entry point for bundlephobia

packages/shared/src/index.ts

@@ -0,0 +1,15 @@
+/*
+Copyright 2019 Adobe. All rights reserved.
+This file is licensed to you 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 REPRESENTATIONS
+OF ANY KIND, either express or implied. See the License for the specific language
+governing permissions and limitations under the License.
+*/
+
+export * from './focus-visible.js';
+export * from './focusable.js';
+export * from './observe-slot-text.js';