build: bump actions/upload-artifact to v4

Author: Scoolnik

.github/workflows/dotnet_nightly.yml

@@ -35,7 +35,7 @@ jobs:
 
       #  Upload artifacts
       - name: Upload BepInEx.Unity.IL2CPP.CoreCLR
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
         with:
           name: CinematicUnityExplorer.BepInEx.Unity.IL2CPP.CoreCLR.zip
           path: ./Release/CinematicUnityExplorer.BepInEx.Unity.IL2CPP.CoreCLR/