head_ref -> base_ref

As no PR will be made  on main (the condition for `head_ref` will always return false).
Replaced with `base_ref` to check if the PR is against main instead.

Author: HellAholic

.github/workflows/package.yml

@@ -34,7 +34,7 @@ jobs:
 
   npm-package:
     needs: [ conan-package ]
-    if: ${{ (github.event_name == 'push' && (github.ref_name == 'main' || startsWith(github.ref_name, 'NP-'))) || (github.event_name == 'pull_request' && github.head_ref == 'main') }}
+    if: ${{ (github.event_name == 'push' && (github.ref_name == 'main' || startsWith(github.ref_name, 'NP-'))) || (github.event_name == 'pull_request' && github.base_ref == 'main') }}
     uses: ultimaker/cura-workflows/.github/workflows/npm-package.yml@main
     with:
       package_version_full: ${{ needs.conan-package.outputs.package_version_full }}