install nix-env engage for gitlab ci

Signed-off-by: strawberry <strawberry@puppygock.gay>

.gitlab-ci.yml

@@ -18,7 +18,7 @@ variables:
 
 before_script:
   # Install direnv and nix-direnv
-  - if command -v nix > /dev/null; then nix-env -iA nixpkgs.direnv nixpkgs.nix-direnv; fi
+  - if command -v nix > /dev/null; then nix-env -iA nixpkgs.direnv nixpkgs.nix-direnv nixpkgs.engage; fi
 
   # Allow .envrc
   - if command -v nix > /dev/null; then direnv allow; fi