Add github action for DBM-Offline

Non-blocking, just testing if it works properly

.github/workflows/dbm-offline.yml

@@ -0,0 +1,26 @@
+name: DBM-Offline test diff
+run-name: DBM-Offline
+
+on:
+  push:
+    branches:
+      - master
+    tags:
+      - "*"
+  pull_request:
+    branches:
+      - master
+
+jobs:
+  dbm-offline-diff:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Run DBM-Offline
+        continue-on-error: true
+        uses: DeadlyBossMods/DBM-Offline@main
+        with:
+          dbm-mod-repo: DeadlyBossMods/DBM-Vanilla
+          dbm-mod-ref: ${{ github.event_name == 'pull_request' && github.event.pull_request.head.sha || github.event.after }}
+          dbm-mod-base-ref: ${{ github.event_name == 'pull_request' && github.event.pull_request.base.sha || github.event.before }}
+          upload-repo: emmericp/test-github-actions
+          upload-token: ${{ secrets.DBM_OFFLINE_UPLOAD_TOKEN }}