Use CSV-separated outputs @ get-changed-files @ CI (python#105151)

Co-authored-by: Hugo van Kemenade <hugovk@users.noreply.github.com>
(cherry picked from commit eaa6702)

Author: webknjaz

.github/workflows/build.yml

@@ -78,6 +78,7 @@ jobs:
             Doc/**
             Misc/**
             .github/workflows/reusable-docs.yml
+          format: csv  # works for paths with spaces
       - name: Check for docs changes
         if: >-
           github.event_name == 'pull_request'