Update tarantool-python submodule

This update contains changes from 0.6.5 release (cited below) and usage
of yaml.safe_load() instead of yaml.load() in tarantool-python tests
(doesn't affect test-run behaviour).

The reason why it is updated here is just to keep things in sync and,
second, to eliminate usage of yaml.load() w/o an explicit loader
everywhere where it is possible. The latter is because it was banned in
recent versions of pyyaml in Gentoo Linux; see [1].

There was also related change 38400e9
('Update pyyaml version') where yaml.load() was replaced with
yaml.safe_load() within test-run itself.

[1]: https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=79ba924d94cb0cf8559565178414c2a1d687b90c

# tarantool-python 0.6.5

## Breaking changes

This release should not break existing code.

## New features

* Added MeshConnection that allows to switch between nodes from a user
  provided list if a current node is down using round-robin strategy (#106).
* Added connection_timeout parameter to Connection (#115).

## Bugfixes

* Fixed auto-reconnection in Connection.
* Eliminated deprecation warnings on Python 3 (#114).
* Added TCP_NODELAY back (it was removed in 0.6.4) (#127).

https://github.com/tarantool/tarantool-python/releases/tag/0.6.5