bump EOL github upload action

Author: davidjumani

.github/workflows/ci.yml

@@ -106,7 +106,7 @@ jobs:
       run: |
         diff inja/inja.hpp inja/inja_old.hpp >/dev/null
 
-    - uses: actions/upload-artifact@v3
+    - uses: actions/upload-artifact@v4
       with:
         name: single_include_inja
         path: single_include/inja/inja.hpp