fix: clear /workspace before clone to avoid 'already exists' error

.gitea/workflows/ci.yml

@@ -20,9 +20,9 @@ jobs:
       - name: Checkout
         run: |
           git config --global http.sslVerify false
+          rm -rf /workspace
           git clone ${{ gitea.server_url }}/${{ gitea.repository }}.git /workspace
-          cd /workspace
-          git checkout ${{ gitea.sha }}
+          cd /workspace && git checkout ${{ gitea.sha }}
         working-directory: /
 
       - name: Install dependencies