Feature Request: Tag Major Versions of Ionic Framework

**Starter Type:** N/A
**Starter Template:** N/A

**Description:**
Working with a customer, I need to scaffold an Ionic Framework v4 application to create a customized upgrade path. With only the `package.json` file available, I require a way to create the correct project structure and contents to test dependency updates.

It would be beneficial if this repository had tags for major versions of the Ionic Framework. While we do end-of-life versions of the Framework, it is helpful in a support capacity to keep some mechanism available to allow us to easily create older Ionic Framework version projects.

**My `ionic info`:**
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**Other Information:**
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