actions: update upload-artifact to v4

Signed-off-by: Kieran Levin <[email protected]>

Author: kiram9

.github/workflows/ci.yml

@@ -31,7 +31,7 @@ jobs:
       run: make COSMOCC=./cosmopolitan
 
     - name: Upload Cosmopolitan EXE
-      uses: actions/upload-artifact@v3
+      uses: actions/upload-artifact@v4
       with:
         name: gpu_cfg_gen.exe
         path: gpu_cfg_gen.exe