Add a "nightly" github actions workflow

To run tests so that breaking changes in rabbitmq-server are detected

Author: HoloRin

.github/workflows/nightly.yml

@@ -0,0 +1,69 @@
+name: Test (Nightly)
+on:
+  schedule:
+  - cron: '0 3 * * *'
+  workflow_dispatch:
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        bazel_otp_name:
+        - "25"
+        branch:
+        - main
+        - v3.12.x
+        - v3.11.x
+    steps:
+    - name: CHECKOUT
+      uses: actions/checkout@v3
+      with:
+        ref: ${{ matrix.branch }}
+    - name: MOUNT BAZEL CACHE
+      uses: actions/cache@v3.3.1
+      with:
+        path: "/home/runner/repo-cache/"
+        key: ${{ runner.os }}-repo-cache-${{ hashFiles('MODULE.bazel','WORKSPACE.bazel') }}
+        restore-keys: |
+          ${{ runner.os }}-repo-cache-
+    - name: CONFIGURE BAZEL
+      run: |
+        if [ -n "${{ secrets.BUILDBUDDY_API_KEY }}" ]; then
+        cat << EOF >> user.bazelrc
+          build:buildbuddy --remote_header=x-buildbuddy-api-key=${{ secrets.BUILDBUDDY_API_KEY }}
+        EOF
+        fi
+        cat << EOF >> user.bazelrc
+          build:buildbuddy --build_metadata=ROLE=CI
+          build:buildbuddy --build_metadata=VISIBILITY=PUBLIC
+          build:buildbuddy --repository_cache=/home/runner/repo-cache/
+          build:buildbuddy --color=yes
+          build:buildbuddy --disk_cache=
+        EOF
+
+        bazelisk info release
+    - name: CONFIGURE rabbitmq-server BRANCH
+      run: |
+        sudo npm install --global --silent @bazel/buildozer
+
+        branch="${{ matrix.branch }}"
+        version="${branch#v}"
+
+        echo "$(cat MODULE.bazel | buildozer 'set strip_prefix "rabbitmq-server-'${version}'"' -:%archive_override)" > MODULE.bazel
+        echo "$(cat MODULE.bazel | buildozer 'set urls ["https://github.com/rabbitmq/rabbitmq-server/archive/refs/heads/${{ matrix.branch }}.zip"]' -:%archive_override)" > MODULE.bazel
+
+        git diff
+    - name: TEST
+      run: |
+        bazelisk test //... \
+          --config=rbe-${{ matrix.bazel_otp_name }} \
+          --verbose_failures
+  summary:
+    needs:
+    - test
+    runs-on: ubuntu-latest
+    steps:
+    - name: SUMMARY
+      run: |
+        echo "SUCCESS"