Run Python checks for any change including deletion (#958)

The condition for running the Python checks needs to include deletion
of Python files, not just addition or modification, because deletion
can cause failures.

.github/workflows/ci.yml

@@ -121,8 +121,7 @@ jobs:
           # The outputs will be variables named "foo_files" for a filter "foo".
           filters: |
             python:
-              - added|modified:
-                  - '**/*.py'
+              - '**/*.py'
             yaml:
               - added|modified:
                   - '**/*.yaml'