fix range

Author: rrousselGit

website/docs/introduction/getting_started.mdx

@@ -41,7 +41,7 @@ If `pub get` is failing due to version solving issues, consider switching to the
 flutter channel beta
 ```
 
-Or consider downgrading Riverpod to `<3.1.0`.
+Or consider downgrading Riverpod to `<=3.1.0`.
 :::