add Actions workflow for syncing with Crowdin (#15999)

* add Actions workflow for syncing with Crowdin

Co-Authored-By: Chiedo John <2156688+chiedo@users.noreply.github.com>

* use the default GitHub token in the Crowdin workflow

Co-Authored-By: Chiedo John <2156688+chiedo@users.noreply.github.com>

* bump to latest version of crowdin/github-action

Co-Authored-By: Chiedo John <2156688+chiedo@users.noreply.github.com>

* allow crowdin/github-action@1.0.10 action

Co-Authored-By: Chiedo John <2156688+chiedo@users.noreply.github.com>

Co-authored-by: Chiedo John <2156688+chiedo@users.noreply.github.com>

.github/allowed-actions.js

@@ -15,6 +15,7 @@ module.exports = [
   'actions/setup-node@v1',
   'actions/setup-ruby@v1',
   'actions/stale@v3',
+  'crowdin/github-action@1.0.10',
   'dawidd6/action-delete-branch@v3',
   'docker://chinthakagodawita/autoupdate-action:v1',
   'github/codeql-action/analyze@v1',

.github/workflows/crowdin.yml

@@ -0,0 +1,50 @@
+# Please ping @github/docs-localization in the PR whenever you update this file!
+
+name: Crowdin Sync
+
+on:
+  push:
+    branches:
+      - main
+
+jobs:
+  sync_with_crowdin:
+    name: Sync with Crowdin
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+
+      - name: Sync
+        uses: crowdin/github-action@1.0.10
+        with:
+          upload_translations: true
+          download_translations: true
+          create_pull_request: true
+          
+          # Using a custom config temporarily to avoid clobbering the existing crowdin.yml
+          # that is used by the github-help-docs OAuth integration.
+          config: 'crowdin-actions-config.yml'
+
+          # This is the name of the git branch that Crowdin will create when opening a pull request.
+          # This branch does NOT need to be manually created. It will be created automatically by the action.
+          localization_branch_name: automated-crowdin-translations
+
+          # This is the name of the top-level directory that Crowdin will use for files.
+          # Note that this is not a "branch" in the git sense, but more like a top-level directory in your Crowdin project.
+          # This branch does NOT need to be manually created. It will be created automatically by the action.
+          crowdin_branch_name: crowdin-main
+
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
+          # This is a numeric id, not to be confused with Crowdin API v1 "project identifier" string
+          # See "API v2" on https://crowdin.com/project/<your-project>/settings#api
+          CROWDIN_PROJECT_ID: ${{ secrets.CROWDIN_PROJECT_ID }}
+          
+          # A personal access token, not to be confused with Crowdin API v1 "API key"
+          # See https://crowdin.com/settings#api-key to generate a token
+          # This token was created by logging into Crowdin with the octoglot user
+          CROWDIN_PERSONAL_TOKEN: ${{ secrets.CROWDIN_PERSONAL_TOKEN }}
+
+