ci: update actions to latest major versions (#1361)

Most of these are motivated by the EOL for Node 16 (for more, see [GitHub's post on it](https://github.blog/changelog/2023-09-22-github-actions-transitioning-from-node-16-to-node-20/)).

.github/workflows/ci.yml

@@ -19,7 +19,7 @@ jobs:
         ruby-version: ["3.0", "3.1", "3.2"]
     runs-on: ${{ matrix.os }}
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Setup Ruby ${{ matrix.ruby-version }}
       uses: ruby/setup-ruby@v1
       with:
@@ -42,7 +42,7 @@ jobs:
     name: Build (github-pages gem)
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Setup Ruby
       uses: ruby/setup-ruby@v1
       with:
@@ -66,7 +66,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Setup Ruby ${{ matrix.ruby-version }}
         uses: ruby/setup-ruby@v1
         with:
@@ -75,14 +75,14 @@ jobs:
           cache-version: 0 # Increment this number if you need to re-download cached gems
       - name: Cache HTMLProofer
         id: cache-htmlproofer
-        uses: actions/cache@v2
+        uses: actions/cache@v3
         with:
           path: tmp/.htmlproofer
           key: ${{ runner.os }}-htmlproofer
       - name: Build Site
         run: bundle exec jekyll build
       - name: Test with Nu Validator
-        uses: Cyb3r-Jak3/html5validator-action@c7bb77a0fe3b0458583de50fd0f4dd819569b8a9
+        uses: Cyb3r-Jak3/html5validator-action@2a593a9f2c10593cbac84791a6fc4c47e9a106c8
         with:
           root: _site
           blacklist: line-numbers
@@ -100,9 +100,9 @@ jobs:
         node-version: [18.x]
 
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Use Node.js ${{ matrix.node-version }}
-      uses: actions/setup-node@v1
+      uses: actions/setup-node@v3
       with:
         node-version: ${{ matrix.node-version }}
     - run: npm install

.github/workflows/deploy.yml

@@ -30,7 +30,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Setup Ruby
         uses: ruby/setup-ruby@v1
         with:
@@ -39,7 +39,7 @@ jobs:
           cache-version: 0 # Increment this number if you need to re-download cached gems
       - name: Setup Pages
         id: pages
-        uses: actions/configure-pages@v2
+        uses: actions/configure-pages@v3
       - name: Build with Jekyll
         # Outputs to the './_site' directory by default
         run: bundle exec jekyll build --baseurl "${{ steps.pages.outputs.base_path }}"
@@ -47,7 +47,7 @@ jobs:
           JEKYLL_ENV: production
       - name: Upload artifact
         # Automatically uploads an artifact from the './_site' directory by default
-        uses: actions/upload-pages-artifact@v1
+        uses: actions/upload-pages-artifact@v2
 
   # Deployment job
   deploy:
@@ -59,4 +59,4 @@ jobs:
     steps:
       - name: Deploy to GitHub Pages
         id: deployment
-        uses: actions/deploy-pages@v1
+        uses: actions/deploy-pages@v2

.github/workflows/publish-gem.yml

@@ -9,7 +9,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Setup Ruby 3.2
       uses: ruby/setup-ruby@v1
       with: