docs: create v2 upgrading guide skeleton (backport #22696)

UPGRADING_v2.md

@@ -0,0 +1,50 @@
+# Upgrading Cosmos SDK v2 [DRAFT, see #22531](https://github.com/cosmos/cosmos-sdk/issues/22531)
+
+This guide provides instructions for upgrading to specific versions of Cosmos SDK.
+Note, always read the **SimApp** section for more information on application wiring updates.
+
+## Upgrading from v0.52.x to v2.
+
+First and foremost, v2 uses [depinject](./depinject/README.md) to wire the module and application dependencies.
+This guide assumes that you have already made your modules depinject compatible, and that you made use of depinject in your application.
+
+### Modules
+
+### Server
+
+
+### SimApp
+
+With the migration to server/v2 and runtime/v2 some changes are required in the `root.go` and `app.go` of your application.
+
+#### `app.go`
+
+
+#### `root.go`
+
+Thanks to the more modular design of v2, the application developer is free to pick which server to use in their application:
+
+```go
+// wire server commands
+return serverv2.AddCommands[T](
+	rootCmd,
+	logger,
+	simApp,
+	deps.GlobalConfig,
+	initServerConfig(),
+	deps.ConsensusServer,
+	grpcServer,
+	storeComponent,
+	telemetryServer,
+	restServer,
+	grpcgatewayServer,
+)
+```
+
+## Upgrading from v0.50.x to v2
+
+Upgrading directly from v0.50.x to v2 is supported.
+Modules should be updated to support all the latest changes in the SDK.
+
+Read the module section from the v0.52 [UPGRADING.md](UPGRADING.md) file for more information.
+Then simply follow the instructions from the [v0.52 section](#upgrading-from-v052x-to-v200) from this file.