ci: downgrade artifact actions to v3 for Gitea compatibility

.gitea/workflows/deploy.yml

@@ -25,7 +25,7 @@ jobs:
       - name: Build
         run: pnpm build
 
-      - uses: actions/upload-artifact@v4
+      - uses: actions/upload-artifact@v3
         with:
           name: doc-build
           path: doc_build/
@@ -36,7 +36,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
-      - uses: actions/download-artifact@v4
+      - uses: actions/download-artifact@v3
         with:
           name: doc-build
           path: doc_build/
@@ -51,7 +51,7 @@ jobs:
     needs: build
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/download-artifact@v4
+      - uses: actions/download-artifact@v3
         with:
           name: doc-build
           path: doc_build/