Add a dynamic security workflow and a SECURITY.md file (#481)

Add a dynamic security workflow that will automatically create PRs to update our Security policies in this repo.

Co-authored-by: sarahraqueld <[email protected]>

.github/workflows/dynamic-security.yml

@@ -0,0 +1,19 @@
+name: update-security
+
+on:
+  push:
+    paths:
+      - SECURITY.md
+    branches:
+      - main
+  workflow_dispatch:
+
+jobs:
+  update-security:
+    permissions:
+      contents: write
+      pull-requests: write
+      pages: write
+    uses: thoughtbot/templates/.github/workflows/dynamic-security.yaml@main
+    secrets:
+      token: ${{ secrets.GITHUB_TOKEN }}

SECURITY.md

@@ -0,0 +1,2 @@
+<!-- START /templates/security.md -->
+<!-- END /templates/security.md -->