Add Github Actions for Crowdin translations management

- an action when merging on `main` which uploads new sources to Crowdin
- an action running once a day, to download translations from Crowdin and create/update a PR with them

.github/workflows/crowdin-download.yml

@@ -0,0 +1,47 @@
+name: Crowdin / Download translations
+on:
+  schedule:
+    - cron: '17 4 * * *' # Every day
+  workflow_dispatch:
+
+permissions:
+  contents: write
+  pull-requests: write
+
+jobs:
+  download-translations:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+
+      - name: Increase Git http.postBuffer
+        # This is needed due to a bug in Ubuntu's cURL version?
+        # See https://github.com/orgs/community/discussions/55820
+        run: |
+          git config --global http.version HTTP/1.1
+          git config --global http.postBuffer 157286400
+
+      - name: crowdin action
+        uses: crowdin/github-action@v1
+        with:
+          upload_sources: false
+          upload_translations: false
+          download_translations: true
+          crowdin_branch_name: main
+          localization_branch_name: i18n/crowdin/translations
+          create_pull_request: true
+          pull_request_title: 'New Crowdin Translations (automated)'
+          pull_request_body: |
+            New Crowdin translations by [Crowdin GH Action](https://github.com/crowdin/github-action)
+
+            See `.github/workflows/crowdin-download.yml
+
+            This PR will be updated every day with new translations.'
+          pull_request_labels: 'i18n'
+
+        env:
+          CROWDIN_PROJECT_ID: ${{ vars.CROWDIN_PROJECT_ID }}
+          CROWDIN_PERSONAL_TOKEN: ${{ secrets.CROWDIN_PERSONAL_TOKEN }}
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

.github/workflows/crowdin-upload.yml

@@ -0,0 +1,35 @@
+name: Crowdin / Upload translations
+
+on:
+  push:
+    branches:
+      - main
+    paths:
+      - crowdin.yml
+      - app/javascript/mastodon/locales/en.json
+      - config/locales/en.yml
+      - config/locales/simple_form.en.yml
+      - config/locales/activerecord.en.yml
+      - config/locales/devise.en.yml
+      - config/locales/doorkeeper.en.yml
+      - .github/workflows/crowdin-upload.yml
+
+jobs:
+  upload-translations:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+
+      - name: crowdin action
+        uses: crowdin/github-action@v1
+        with:
+          upload_sources: true
+          upload_translations: false
+          download_translations: false
+          crowdin_branch_name: main
+
+        env:
+          CROWDIN_PROJECT_ID: ${{ vars.CROWDIN_PROJECT_ID }}
+          CROWDIN_PERSONAL_TOKEN: ${{ secrets.CROWDIN_PERSONAL_TOKEN }}

crowdin.yml

@@ -1,5 +1,10 @@
+# This is needed for the Github Action
+project_id_env: CROWDIN_PROJECT_ID
+api_token_env: CROWDIN_PERSONAL_TOKEN
+
 skip_untranslated_strings: 1
 commit_message: '[ci skip]'
+preserve_hierarchy: true
 files:
   - source: /app/javascript/mastodon/locales/en.json
     translation: /app/javascript/mastodon/locales/%two_letters_code%.json