Update .drone.yml

.drone.yml

@@ -4,10 +4,16 @@ name: default
 steps:
 - name: git-clone
   image: alpine/git
+  environment:
+    SSH_KEY:
+      from_secret: ssh_key
   volumes:
   - name: output
     path: /output
   commands:
+    - echo "$SSH_KEY" > $HOME/.ssh/id_rsa
+    - chmod 600 $HOME/.ssh/known_hosts
+    - ssh-keyscan -H git@git.ericxliu.me > ~/.ssh/known_hosts 2> /dev/null
     - git clone --branch gitea-pages git@git.ericxliu.me:eric/ericxliu-me.git /output
 - name: build
   image: plugins/hugo