feat: enable release-please releases and back-sync trigger

Stainless-Generated-From: 2ee3fa88007964f7781dd5ac949b48211732a9a0

Author: adonis-sh

.github/workflows/release-please.yml

@@ -0,0 +1,20 @@
+name: Release Please
+on:
+  push:
+    branches:
+      - main
+
+permissions:
+  contents: write
+  pull-requests: write
+
+jobs:
+  release-please:
+    if: github.repository == 'sentdm/sent-dm-python'
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: googleapis/release-please-action@5c625bfb5d1ff62eadeeb3772007f7f66fdcf071 # v4.4.1
+        id: release
+        with:
+          token: ${{ secrets.RELEASE_PLEASE_TOKEN }}