Remove obsolete workflow transferring source across forks (#326)

.github/workflows/push-browsermt-main-to-mozilla-main.yml

@@ -1,27 +0,0 @@
-name: Push browsermt/main branch to mozilla/bergamot-translator
-
-on:
-  schedule:
-  # Run every hour
-  - cron: "0 * * * *"
-
-  workflow_dispatch:
-
-jobs:
-  build:
-    runs-on: ubuntu-latest
-    name: Mirror a branch from a remote repo into this one
-    env:
-      source_repository: 'browsermt/bergamot-translator'
-      this_repository: 'mozilla/bergamot-translator'
-      branch: 'main'
-    steps:
-      - uses: actions/checkout@v2
-
-      - name: Mirror a branch from a remote repo into this one
-        if: ${{ github.repository == env.this_repository }}
-        run: |
-          git clone -b ${{ env.branch }} https://github.com/${{ env.source_repository }}.git source
-          cd source
-          git remote add mirror https://x-access-token:${{ secrets.GITHUB_TOKEN }}@github.com/${{ env.this_repository }}.git
-          git push mirror ${{ env.branch }}