Workflow to sync strings (#18965)

.github/workflows/sync-strings.yml

@@ -0,0 +1,43 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/
+
+name: "Sync Strings"
+
+on:
+  schedule:
+    - cron: '0 */4 * * *'
+
+jobs:
+  main:
+    name: "Sync Strings"
+    runs-on: ubuntu-20.04
+    steps:
+      - name: "Discover Fenix Beta Version"
+        id: fenix-beta-version
+        uses: mozilla-mobile/fenix-beta-version@1.0.0
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+      - name: "Checkout Master Branch"
+        uses: actions/checkout@v2
+        with:
+          path: main
+          ref: master
+      - name: "Checkout Beta Branch"
+        uses: actions/checkout@v2
+        with:
+          path: beta
+          ref: "releases_v${{ steps.fenix-beta-version.outputs.fenix-beta-version }}.0.0"
+      - name: "Sync Strings"
+        uses: mozilla-mobile/sync-strings-action@1.0.0
+        with:
+          src: main
+          dst: beta
+      - name: Create Pull Request
+        uses: peter-evans/create-pull-request@v3
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}
+          path: beta
+          branch: automation/sync-strings-${{ steps.fenix-beta-version.outputs.major-beta-version }}
+          title: "Sync Strings from master to releases_${{steps.fenix-beta-version.outputs.fenix-beta-version}}.0"
+          body: "This (automated) PR syncs strings from `master` to `releases_${{steps.fenix-beta-version.outputs.fenix-beta-version}}.0.0`"