github: Update actions so they don't use deprecated Node.js 20

.github/workflows/cifuzz.yml

@@ -40,7 +40,7 @@ jobs:
         sanitizer: ${{ matrix.sanitizer }}
 
     - name: Upload Crash
-      uses: actions/upload-artifact@v4
+      uses: actions/upload-artifact@v6
       if: failure() && steps.build.outcome == 'success'
       with:
         name: ${{ matrix.sanitizer }}-artifacts