feat: support SWR v2

[koba04]

refs. https://github.com/vercel/swr/releases/tag/2.0.0-beta.0

SWR v2 has changed the internal structure of the cache data, so DevTools has to support the new data structure.

SWR DevTools has 3 packages, which are swr-devtools, swr-devtools-panel, and swr-devtools-extensions.

• swr-devtools is a package that developers install and put it into their application
• swr-devtools-panel is a package used in a browser extension panel
• swr-devtools-extensions is a package to be run as a background script

swr-devtools is installed by application developers, so this doesn't have to deal with either SWR v1 or v2.
swr-devtools-panel and swr-devtools-extensions are installed from store of extensions, so developers always have to use the latest version. It means that swr-devtools-panel and swr-devtools-extensions have to support SWR v1 and v2.

My strategy is the following.

• [ ] 1. swr-devtools converts the cache data from SWR v1 format to v2 and sends the data
• [ ] 2. swr-devtools-panel and swr-devtools-extensions support SWR v2 format
• [ ] 3. swr-devtools supports SWR v2 in the next major version

I've added v1 and v2 support into swr-devtools-panel because I think it's a minimum way to achieve this.

[vercel]

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Name	Status	Preview	Updated
swr-devtools	✅ Ready (Inspect)	Visit Preview	May 26, 2022 at 3:32PM (UTC)

[koba04]

This drops the support of <1.2.0 versions because v1.2.0 has changed the format of cache data.
vercel/swr#1752

I could keep supporting those versions, but it seems to be acceptable for me.

I've fixed it.