Add scrip to mirror repo to gitee

.github/workflows/mirror.yaml

@@ -0,0 +1,27 @@
+name: Mirroring
+
+# yamllint disable-line rule:truthy
+on:
+  push:
+    branches:
+      - master
+      - dev
+
+jobs:
+  mirror_gitee:
+    name: Mirror to Gitee
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+        with:
+          fetch-depth: 0
+      - name: Push to Gitee
+        env:
+          SSH_KEY: ${{ secrets.GITEE_KEY }}
+        run: |
+          mkdir -p ~/.ssh
+          echo "${SSH_KEY}" > ~/.ssh/id_rsa
+          chmod 600 ~/.ssh/id_rsa
+          export GIT_SSH_COMMAND="ssh -o StrictHostKeyChecking=no -l git"
+          git remote add gitee git@gitee.com:shenxn/protonmail-bridge-docker.git
+          git push --tags --force --prune gitee "refs/remotes/origin/*:refs/heads/*"