updated GitHub actions

Author: dg

.github/workflows/tests.yml

@@ -21,7 +21,7 @@ jobs:
             - run: composer install --no-progress --prefer-dist
             - run: vendor/bin/tester tests -s
             - if: failure()
-              uses: actions/upload-artifact@v3
+              uses: actions/upload-artifact@v4
               with:
                   name: output
                   path: tests/**/output