docs: Add edge releases channel

Author: atinux

docs/content/3.guide/4.migration/2.edge-channel.md

@@ -0,0 +1,44 @@
+---
+title: Edge Channel
+description: Nuxt Content is landing commits, improvements, and bug fixes every day. You can opt-in to test them earlier before the next release.
+---
+
+After each commit is merged into the `main` branch of [nuxt/content](https://github.com/nuxt/content) and **passing all tests**, we trigger an automated npm release using Github Actions publishing a `@nuxt/content-edge` package.
+
+You can opt in to use this release channel and avoid waiting for the next release and helping the module by beta testing changes.
+
+The build and publishing method and quality of edge releases are the same as stable ones. The only difference is that you should often check the [GitHub repository](https://github.com/nuxt/content) for updates. There is a slight chance of regressions not being caught during the review process and by the automated tests. Therefore, we internally use this channel to double-check everything before each release.
+
+::alert
+Features only available on the edge channel are marked with an alert in the documentation.
+::
+
+## Opting into the edge channel
+
+Update `@nuxt/content` dependency inside `package.json`:
+
+```diff [package.json]
+{
+  "devDependencies": {
+--    "@nuxt/content": "^2.0.0"
+++    "@nuxt/content": "npm:@nuxt/content@latest"
+  }
+}
+```
+
+Remove lockfile (`package-lock.json`, `yarn.lock`, or `pnpm-lock.yaml`) and reinstall dependencies.
+
+## Opting out from the edge channel
+
+Update `@nuxt/content` dependency inside `package.json`:
+
+```diff [package.json]
+{
+  "devDependencies": {
+--    "@nuxt/content": "npm:@nuxt/content@latest"
+++    "@nuxt/content": "^2.0.0"
+  }
+}
+```
+
+Remove lockfile (`package-lock.json`, `yarn.lock`, or `pnpm-lock.yaml`) and reinstall dependencies.