Don't run docs deploy step on PRs in template

Author: matt-graham

{{cookiecutter.project_slug}}/.github/workflows/docs.yml

@@ -47,6 +47,7 @@ jobs:
       id-token: write
     runs-on: ubuntu-latest
     needs: build
+    if: github.event_name != 'pull_request'
     steps:
       - name: Deploy to GitHub Pages
         id: deployment