Downgrade download-artifact to v3

actions/download-artifact#290 (comment)

Author: skibitsky

.github/workflows/main.yml

@@ -59,7 +59,7 @@ jobs:
         with:
           fetch-depth: 0
       - name: Download WebGL Build Artifact
-        uses: actions/download-artifact@v4.1.8
+        uses: actions/download-artifact@v3
         with:
           name: Build-WebGL
           path: Build/WebGL