Update donate.yml

.github/workflows/donate.yml

@@ -17,9 +17,9 @@ jobs:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
           TOOL: "https://github.com/jollheef/donate/archive/master.tar.gz"
         run: |
-          curl https://nixos.org/nix/install | sh
+          curl -L https://nixos.org/nix/install | sh
           . ~/.nix-profile/etc/profile.d/nix.sh
           # Use latest stable nixpkgs channel
-          nix-channel --add https://nixos.org/channels/nixos-19.09 nixpkgs
+          nix-channel --add https://nixos.org/channels/nixos-20.03 nixpkgs
           nix-channel --update
           nix run -f $TOOL -c donate-ci