.github: Output expected vs. actual (#67703)

Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/67703

Had this script fail on me within CI without actually telling me what
was wrong so adding some more output here to showcase what the actual
vs. the expected result is

Signed-off-by: Eli Uriegas <eliuriegas@fb.com>

Test Plan: Imported from OSS

Reviewed By: janeyx99

Differential Revision: D32112898

Pulled By: seemethere

fbshipit-source-id: dfc9a82c709d52e0dde02d1e99a19eecc63c5836

.github/scripts/ensure_actions_will_cancel.py

@@ -46,11 +46,20 @@ if __name__ == "__main__":
             "group": concurrency_key(filename),
             "cancel-in-progress": True,
         }
-        if data.get("concurrency", None) != expected:
+        actual = data.get("concurrency", None)
+        if actual != expected:
             print(
                 f"'concurrency' incorrect or not found in '{filename.relative_to(REPO_ROOT)}'",
                 file=sys.stderr,
             )
+            print(
+                f"expected: {expected}",
+                file=sys.stderr,
+            )
+            print(
+                f"actual:   {actual}",
+                file=sys.stderr,
+            )
             errors_found = True
 
     if errors_found: