Fix "if" tests to get the right behavior.

Author: billnapier

.github/workflows/publish_docs.yml

@@ -19,14 +19,15 @@ jobs:
         src: 'docs'
         dst: 'generated-pages'
     - name: 'Upload artifact'
+      if: github.ref == 'refs/heads/main'
       uses: 'actions/upload-pages-artifact@v3'
       with:
         path: 'generated-pages'
     - name: 'Deploy GitHub Pages Preview'
-      if: github.ref == 'refs/heads/main'
+      if: github.ref != 'refs/heads/main'
       uses: rossjrw/pr-preview-action@v1
       with:
-        source-dir: ./generated-pages/
+        source-dir: './generated-pages/'
   deploy:
     if: github.ref == 'refs/heads/main'
     environment: