Update GitHub Actions to use v4 artifacts and dependency review

- Update actions/upload-artifact from v3 to v4
- Update actions/dependency-review-action from v3 to v4
- Fix deprecated action warnings

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

.github/workflows/benchmark.yml

@@ -36,7 +36,7 @@ jobs:
         run: cargo bench --no-fail-fast
 
       - name: Upload benchmark results
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
         with:
           name: benchmark-results
           path: target/criterion/

.github/workflows/ci.yml

@@ -157,7 +157,7 @@ jobs:
         run: cargo build --release --target ${{ matrix.target }} --verbose
 
       - name: Upload artifact
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
         with:
           name: piglet-${{ matrix.target }}
           path: |

.github/workflows/security.yml

@@ -31,4 +31,4 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Dependency Review
-        uses: actions/dependency-review-action@v3
+        uses: actions/dependency-review-action@v4