Add workflow to trigger build

(cherry picked from commit 674531c)

.github/dependabot.yml

@@ -0,0 +1,9 @@
+# Please see the documentation for all configuration options:
+# https://docs.github.com/github/administering-a-repository/configuration-options-for-dependency-updates
+version: 2
+updates:
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "daily"
+    target-branch: "main"

.github/workflows/trigger-build.yml

@@ -0,0 +1,21 @@
+name: Trigger build
+
+on:
+  push:
+  workflow_dispatch:
+
+jobs:
+  trigger-build:
+    runs-on: ubuntu-22.04
+    steps:
+      - name: Extract Erlang major version
+        run: |
+          major=$(echo "${{ github.ref_name }}" | cut -d "-" -f 2)
+          echo $major
+          echo "erlang_major=$major" >> $GITHUB_ENV
+      - name: Trigger build
+        uses: peter-evans/repository-dispatch@v2
+        with:
+          repository: rabbitmq/erlang-packages
+          token: ${{ secrets.CI_GITHUB_TOKEN }}
+          event-type: rpm_erlang_${{ env.erlang_major }}