Run pages build on PRs that touch docs.

.github/workflows/pages.yml

@@ -1,17 +1,17 @@
-# This workflow uses actions that are not certified by GitHub.
-# They are provided by a third-party and are governed by
-# separate terms of service, privacy policy, and support
-# documentation.
-
-# Sample workflow for building and deploying a Jekyll site to GitHub Pages
 name: Deploy Jekyll site to Pages
 
 on:
+  # Run on merges to main branch
   push:
     branches:
       - main
 
-  # Allows you to run this workflow manually from the Actions tab
+  # Run on any PRs that touch the docs directory
+  pull_request:
+    paths:
+      - docs/**
+
+  # Run manually from the Actions tab
   workflow_dispatch:
 
 # Sets permissions of the GITHUB_TOKEN to allow deployment to GitHub Pages
@@ -48,9 +48,7 @@ jobs:
       - name: Build with Jekyll
         working-directory: docs
         # Outputs to the './_site' directory by default
-        run:
-          bundle exec jekyll build --baseurl "${{ steps.pages.outputs.base_path
-          }}"
+        run: bundle exec jekyll build --baseurl "${{ steps.pages.outputs.base_path }}"
         env:
           JEKYLL_ENV: production
       - name: Upload artifact
@@ -61,6 +59,7 @@ jobs:
 
   # Deployment job
   website-deploy:
+    if: github.ref == 'refs/heads/main' # only deploy from main
     environment:
       name: github-pages
       url: ${{ steps.deployment.outputs.page_url }}