Update .github/workflows/dependabot-auto-merge.yml

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: joelhawksley

.github/workflows/dependabot-auto-merge.yml

@@ -1,6 +1,8 @@
 name: Dependabot auto-merge
 
-on: pull_request
+on:
+  pull_request:
+    types: [opened]
 
 permissions:
   contents: write