feat(checkpoint-sync): upgrade upload-artifact action to v4

The action was upgraded to the latest major version.

Author: samcm

.github/actions/checkpoint-sync/action.yaml

@@ -228,12 +228,12 @@ runs:
           fi
           sleep 1;
         done;
-    - uses: actions/upload-artifact@v3
+    - uses: actions/upload-artifact@v4
       if: ${{ always() }}
       with:
         name: ${{ inputs.network }}-${{ inputs.consensus }}-checkpointz.log
         path: logs/checkpointz.log
-    - uses: actions/upload-artifact@v3
+    - uses: actions/upload-artifact@v4
       if: ${{ always() }}
       with:
         name: ${{ inputs.network }}-${{ inputs.consensus }}-consensus.log