Merge pull request #5152 from Olexandr88/patch-1

Replaced the broken link nix

Author: teodanciu

README.md

@@ -86,7 +86,7 @@ The directory structure of this repository is as follows:
 
 # Building
 
-It is recommended to use [`nix`](https://nixos.org/nix/download.html) for building everything in this repository. Make sure you have a recent version of `nix` by following this [guide](https://nixos.org/manual/nix/stable/installation/upgrading.html).
+It is recommended to use [`nix`](https://nixos.org/download.html) for building everything in this repository. Make sure you have a recent version of `nix` by following this [guide](https://nixos.org/manual/nix/stable/installation/upgrading.html).
 
 Haskell files can be built with [`cabal`](https://www.haskell.org/cabal/) inside of a nix shell, which can be entered by invoking `nix develop` from the root directory.