Update dotnet/arcade digest to 644c081 (#19308)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/backport.yml

@@ -16,7 +16,7 @@ permissions:
 jobs:
   backport:
     if: ${{ contains(github.event.comment.body, '/backport to') || github.event_name == 'schedule' }}
-    uses: dotnet/arcade/.github/workflows/backport-base.yml@b36a3594d11b8d56bf7d3dbce919e0688715d5ec # main
+    uses: dotnet/arcade/.github/workflows/backport-base.yml@644c08195994197a9b7e335f2d8488585044e62a # main
     with:
       repository_owners: 'OrchardCMS'