Update GitHub Artifact Actions

Author: renovate[bot]

.github/workflows/build-libwebp.yml

@@ -129,7 +129,7 @@ jobs:
           fi
 
       - name: Upload artifact
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v7
         with:
           name: libwebp-${{ matrix.target }}
           path: output/${{ matrix.artifact }}
@@ -144,7 +144,7 @@ jobs:
       - uses: actions/checkout@v6
 
       - name: Download all artifacts
-        uses: actions/download-artifact@v4
+        uses: actions/download-artifact@v8
         with:
           path: artifacts