Add push to Gitlab action. (#966)

* Add push to Gitlab action.

* Only push 2.x branch.

.github/workflows/gitlab-mirror.yml

@@ -0,0 +1,23 @@
+name: Mirror and run GitLab CI
+
+on:
+  push:
+    branches: [2.x]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v1
+    - name: Mirror + trigger CI
+      uses: SvanBoxel/gitlab-mirror-and-ci-action@master
+      with:
+        args: "https://git.drupalcode.org/project/islandora"
+      env:
+        FOLLOW_TAGS: "true"
+        FORCE_PUSH: "false"
+        GITLAB_HOSTNAME: "git.drupal.org"
+        GITLAB_USERNAME: "project_34868_bot"
+        GITLAB_PASSWORD: ${{ secrets.GITLAB_PASSWORD }}
+        GITLAB_PROJECT_ID: "34868"
+        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}