Buildkite: Final fixes for hackage.nix/stackage.nix updates

Author: rvl

.buildkite/updates.yml

@@ -27,3 +27,5 @@ steps:
       - 'buildkite-agent artifact download "*.json" .'
       - nix-build -A maintainer-scripts.update-pins -o update-pins.sh
       - ./update-pins.sh
+    agents:
+      system: x86_64-linux

scripts/update-pins.nix

@@ -4,7 +4,7 @@ with stdenv.lib;
 
 let
   repo = "git@github.com:input-output-hk/haskell.nix.git";
-  sshKey = "/run/keys/buildkite-haskell-nix-ssh-private";
+  sshKey = "/run/keys/buildkite-haskell-dot-nix-ssh-private";
 in
   writeScript "update-pins.sh" ''
     #!${stdenv.shell}