try different working directory

.github/workflows/main.yml

@@ -4,11 +4,13 @@ jobs:
   nikola_build:
     runs-on: ubuntu-latest
     name: 'Deploy Nikola to GitHub Pages'
+    defaults:
+      run:
+        working-directory: ./site
     steps:
     - name: Check out
       uses: actions/checkout@v2
     - name: Build and Deploy Nikola
       uses: getnikola/nikola-action@v4
       with:
         dry_run: false
-      working-directory: ./site