Merge pull request #1036 from pq-code-package/fix/1033-action-error

Fixes #1033: CI step nix-post-check fails

Author: mkannwischer

.github/actions/setup-nix/action.yml

@@ -90,7 +90,7 @@ runs:
 
         echo "cache_prefix=$cache_prefix" >> $GITHUB_OUTPUT
 
-        if [[ ${{ steps.nix-pre-check.outputs.installed }} == 'false' ]]; then
+        if [[ "${{ steps.nix-pre-check.outputs.installed }}" == 'false' ]]; then
           sudo chown -R $USER:nixbld /nix
         fi