Create Vercel URL alias for pushed version tags

[shawnbot]

This adds an "alias" workflow that creates a Vercel deployment URL alias whenever a tag beginning with v is created. For instance, when we tag the next major release with v7.0.0, the workflow should run and create an alias from formio-sfds-v7-0-0.vercel.app to the current production deployment.

The point of this is to make it easier to compare rendered examples in different versions of our theme.

In the future, these aliases could also power a dropdown on the site that allows you to see the examples and docs as of a specific version by changing the hostname of the current URL. I'm going to manually add aliases for a few recent versions by going down the production deployments list. I don't think there's any need to automate doing the retroactive aliases for versions earlier than, say, 6.3.0.

[vercel[bot]]

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🔍 Inspect: https://vercel.com/sfds/formio-sfds/rep4k3ev2
✅ Preview: https://formio-sfds-git-vercel-alias-version.sfds.vercel.app

[github-actions[bot]]

Size Change: +5.87 kB (6%) 🔍

Total Size: 92 kB

Filename	Size	Change
dist/examples.js	3.51 kB	+320 B (9%)	🔍
dist/formio-sfds.css	14 kB	-14 B (0%)
dist/formio-sfds.standalone.js	68.1 kB	+5.57 kB (8%)	🔍
dist/portal.js	5.36 kB	-10 B (0%)

ℹ️ View Unchanged

| Filename | Size | Change | | |:--- |:---:|:---:|:---:| | `dist/common.css` | 484 B | 0 B | | | `dist/examples/example.js` | 508 B | 0 B | |

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