ci: Migrate pkgdown site deployment to GitHub Pages workflow

Co-authored-by: aider (gemini/gemini-2.5-pro) <aider@aider.chat>

Author: osorensen

.Rbuildignore

@@ -4,3 +4,5 @@
 ^data-raw$
 ^dev$
 ^\.github$
+^_pkgdown\.yml$
+^docs/

.github/workflows/pkgdown.yml

@@ -1,21 +1,20 @@
 on:
   push:
-    branches:
-      - main
-      - master
+    branches: [main]
   workflow_dispatch:
 
 name: pkgdown
 
 jobs:
   pkgdown:
     runs-on: ubuntu-latest
-    env:
-      GITHUB_PAT: ${{ secrets.GITHUB_TOKEN }}
     permissions:
-      contents: write
+      contents: read
+      pages: write
+      id-token: write
+
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
 
       - uses: r-lib/actions/setup-r@v2
         with:
@@ -26,6 +25,23 @@ jobs:
           extra-packages: any::pkgdown, local::.
           needs: pkgdown
 
-      - name: Build and deploy site
-        run: pkgdown::build_site_github_pages()
+      - name: Build site
+        run: pkgdown::build_site_github_pages(new_process = FALSE, install = FALSE)
         shell: Rscript {0}
+
+      - name: Upload artifact
+        uses: actions/upload-pages-artifact@v3
+        with:
+          path: ./docs
+
+  deploy:
+    needs: pkgdown
+    runs-on: ubuntu-latest
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+
+    steps:
+      - name: Deploy to GitHub Pages
+        id: deployment
+        uses: actions/deploy-pages@v4

_pkgdown.yml

@@ -20,3 +20,23 @@ reference:
       - set_hyperparameters
       - set_smc_options
       - precompute_topological_sorts
+url: https://oystein-sorensen.github.io/BayesMallowsSMC2
+template:
+  bootstrap: 5
+  bootswatch: cosmo
+
+home:
+  sidebar:
+    structure: [links, license, community, citation, authors, dev]
+
+navbar:
+  structure:
+    left:  [reference, news]
+    right: [github]
+  components:
+    reference:
+      text: Reference
+      href: reference/index.html
+    news:
+      text: Changelog
+      href: news/index.html