Add reference to the bootstrap migration

Signed-off-by: gtseres <george.tseres@gmail.com>

docs/guides/flux-v1-migration.md

@@ -60,7 +60,7 @@ Flux v1 repository to the bootstrap one.
 ## In-place migration
 
 !!! warning
-    For production use we recommend using the **bootstrap** procedure,
+    For production use we recommend using the **bootstrap** procedure (see the `Gitops migration` section above),
     but if you wish to install Flux v2 in the 
     same way as Flux v1 then follow along.