ci: fix doc build

.github/workflows/ci.yml

@@ -52,15 +52,20 @@ jobs:
       COVERITY_SCAN_TOKEN: ${{ secrets.COVERITY_SCAN_TOKEN }}
 
   antora:
-    if: ${{ (github.repository_owner == 'boostorg' && github.ref_name == 'master') || (github.repository_owner == 'jll63' && github.ref_name == 'feature/doc') }}
-    name: Antora Docs
-    runs-on: ubuntu-latest
+    name: Antora docs
+    strategy:
+      matrix:
+        include:
+          - { name: Windows, os: windows-latest }
+          - { name: Ubuntu, os: ubuntu-latest }
+          - { name: macOS, os: macos-15 }
+    runs-on: ${{ matrix.os }}
     defaults:
       run:
         shell: bash
     steps:
       - name: Install packages
-        uses: alandefreitas/cpp-actions/package-install@v1.8.10
+        uses: alandefreitas/cpp-actions/package-install@v1.8.8
         with:
           apt-get: git cmake
 
@@ -68,7 +73,7 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Clone Boost
-        uses: alandefreitas/cpp-actions/boost-clone@v1.8.10
+        uses: alandefreitas/cpp-actions/boost-clone@v1.8.8
         id: boost-clone
         with:
           branch: ${{ (github.ref_name == 'master' && github.ref_name) || 'develop' }}
@@ -80,7 +85,11 @@ jobs:
         with:
           node-version: 18
 
-      - name: Build Antora Docs
+      - name: Setup Ninja
+        if: runner.os == 'Windows'
+        uses: seanmiddleditch/gha-setup-ninja@v5
+
+      - name: Build Antora docs
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
         run: |
@@ -89,27 +98,30 @@ jobs:
           cd ..
           BOOST_SRC_DIR="$(pwd)/boost-source"
           export BOOST_SRC_DIR
-          cd openmethod
 
+          cd openmethod
           cd doc
           bash ./build_antora.sh
 
-          # Antora returns zero even if it fails, so we check if the site directory exists
-          if [ ! -d "build/site" ]; then
+          # Antora returns zero even if it fails, so we check if the site directory exists.
+          if [ ! -d "html" ]
+          then
               echo "Antora build failed"
               exit 1
           fi
 
-      - name: Create Antora Docs Artifact
+      - name: Create Antora docs artifact
         uses: actions/upload-artifact@v4
         with:
           name: antora-docs-${{ matrix.name }}
-          path: doc/build/site
+          path: doc/html
 
       - name: Upload static files as artifact
+        if: matrix.os == 'ubuntu-latest'
         uses: actions/upload-pages-artifact@v3
         with:
           path: doc/build/site
 
-      - name: Deploy to GitHub Pages
+      - name: Deploy to GitHub Pages (jll63)
+        if: matrix.os == 'ubuntu-latest' && github.repository_owner == 'jll63' && github.ref_name == 'feature/doc'
         uses: actions/deploy-pages@v4