ci: add checkout step to pub.dev workflow (#30)

.github/workflows/pub.dev.yml

@@ -3,7 +3,7 @@ name: Publish to pub.dev
 on:
   push:
     tags:
-      - '[0-9]+.[0-9]+.[0-9]+*' # Tag must be the trigger, defined on pub.dev in the package settings
+      - "[0-9]+.[0-9]+.[0-9]+*" # Tag must be the trigger, defined on pub.dev in the package settings
 # https://dart.dev/tools/pub/automated-publishing#hardening-security-with-tag-protection-rules-on-github
 jobs:
   publish:
@@ -12,6 +12,11 @@ jobs:
     permissions:
       id-token: write # Required for authentication using OIDC
     steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+          ssh-key: ${{ secrets.BOT_SSH_PRIVATE_KEY }}
+
       - name: Setup Flutter SDK
         uses: flutter-actions/setup-flutter@v3
         with: