[stubsabot] Bump braintree to 4.40.*

Release: https://pypi.org/pypi/braintree/4.40.0
Homepage: https://developer.paypal.com/braintree/docs/reference/overview
Repository: https://github.com/braintree/braintree_python
Typeshed stubs: https://github.com/python/typeshed/tree/main/stubs/braintree
Diff: braintree/braintree_python@4.39.0...4.40.0

Stubsabot analysis of the diff between the two releases:
 - 0 public Python files have been added.
 - 0 files included in typeshed's stubs have been deleted.
 - 3 files included in typeshed's stubs have been modified or renamed: `braintree/error_codes.py`, `braintree/transaction.py`, `braintree/version.py`.
 - Total lines of Python code added: 191.
 - Total lines of Python code deleted: 15.

If stubtest fails for this PR:
- Leave this PR open (as a reminder, and to prevent stubsabot from opening another PR)
- Fix stubtest failures in another PR, then close this PR

Note that you will need to close and re-open the PR in order to trigger CI

Author: stubsabot

stubs/braintree/METADATA.toml

@@ -1,2 +1,2 @@
-version = "4.39.*"
+version = "4.40.*"
 upstream_repository = "https://github.com/braintree/braintree_python"