Update GitHub Actions workflows to use latest checkout and upload artifact actions

- Updated the checkout action from v4 to v6 for improved functionality and security.
- Updated the upload artifact action from v3 to v4 to leverage new features and enhancements.

Author: TKorr

.github/workflows/jekyll-gh-pages.yml

@@ -27,7 +27,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
       - name: Setup Pages
         uses: actions/configure-pages@v5
       - name: Build with Jekyll
@@ -36,7 +36,7 @@ jobs:
           source: ./
           destination: ./_site
       - name: Upload artifact
-        uses: actions/upload-pages-artifact@v3
+        uses: actions/upload-pages-artifact@v4
 
   # Deployment job
   deploy:

.github/workflows/rust-clippy.yml

@@ -28,7 +28,7 @@ jobs:
       actions: read # only required for a private repository by github/codeql-action/upload-sarif to get the Action run status
     steps:
       - name: Checkout code
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       - name: Install Rust toolchain
         uses: actions-rs/toolchain@16499b5e05bf2e26879000db0c1d13f7e13fa3af #@v1