Apply suggestion from @lwasser

Author: lwasser

.github/workflows/build-book.yml

@@ -53,7 +53,7 @@ jobs:
 
       # Save html as artifact
       - name: Save book html as artifact for viewing
-        uses: actions/upload-artifact@v5
+        uses: actions/upload-artifact@330a01c490aca151604b8cf639adc76d48f6c5d4 # v5.0.0
         with:
           name: book-html
           path: |