fix suffix parsing for staging releases

Author: olirice

.github/workflows/ami-release-nix.yml

@@ -55,7 +55,7 @@ jobs:
       - name: Run checks if triggered manually
         if: ${{ github.event_name == 'workflow_dispatch' }}
         run: |
-          SUFFIX=$(sudo nix run nixpkgs#yq -- '.postgres_release["postgres${{ matrix.postgres_version }}"]' ansible/vars.yml | sed -E 's/[0-9\.]+(.*)$/\1/')
+          SUFFIX=$(sudo nix run nixpkgs#yq -- ".postgres_release[\"postgres${{ matrix.postgres_version }}\"]" ansible/vars.yml | sed -E 's/[0-9\.]+(.*)$/\1/')
           if [[ -z $SUFFIX ]] ; then
             echo "Version must include non-numeric characters if built manually."
             exit 1