docs: add a section about the legacy CLI (#1227)

Author: remyleone

README.md

@@ -7,11 +7,7 @@
 
 # Scaleway CLI (v2)
 
-If you are looking for Scaleway CLI v1, [you can find it on the v1 branch](https://github.com/scaleway/scaleway-cli/tree/v1).
-
-Scaleway is a single way to create, deploy and scale your infrastructure in the cloud. We help thousands of businesses to run their infrastructures easily.
-
-If you are looking for a stable version, [see the version 1](https://github.com/scaleway/scaleway-cli/tree/master).
+Scaleway CLI is a tool to help you pilot your Scaleway infrastructure directly from your terminal.
 
 # Installation
 
@@ -204,6 +200,11 @@ See more in-depth information about running the CLI in Docker [here](./docs/dock
 This repository is at its early stage and is still in active development.
 If you are looking for a way to contribute please read [CONTRIBUTING.md](CONTRIBUTING.md).
 
+# Legacy version
+
+If you are looking for the legacy CLIv1 you can take a look at the [v1 branch](https://github.com/scaleway/scaleway-cli/blob/v1/README.md).
+We also wrote [a migration guide](./docs/migration_guide_v2.md) to help transition to the CLIv2.
+
 # Reach Us
 
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