added crowdin workflow

.github/workflows/crowdin.yml

@@ -0,0 +1,39 @@
+name: Crowdin
+
+on:
+  schedule:
+    - cron: '0 0 * * *'
+  workflow_dispatch:
+
+jobs:
+  sync:
+    name: Sync
+
+    runs-on: ubuntu-latest
+
+    steps:
+
+    - name: Checkout
+      uses: actions/checkout@v2
+
+    - name: Sync with Crowdin
+      uses: crowdin/github-action@master
+      with:
+        upload_sources: true
+        upload_translations: true
+        download_translations: true
+        skip_untranslated_files: true
+
+        source: 'resources/lang/en-GB/*.php'
+        translation: 'resources/lang/%locale%/%original_file_name%'
+
+        localization_branch_name: 'crowdin'
+        commit_message: 'new crowdin translations'
+        pull_request_title: 'New Crowdin translations'
+        pull_request_body: 'https://crowdin.com/project/akaunting'
+        pull_request_labels: 'Translation'
+        
+        project_id: ${{ secrets.CROWDIN_CORE_ID }}
+        token: ${{ secrets.CROWDIN_PERSONAL_TOKEN }}
+      env:
+        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}