Update pymodbustcp to 0.1.9

[pyup-bot]

This PR updates pyModbusTCP from 0.1.8 to 0.1.9.

Changelog

0.1.9

- add module error MB_SOCK_CLOSE_ERR (occur if frame send on close socket).
 - add modbus exception EXP_NEGATIVE_ACKNOWLEDGE (code 0x07) to constants.
 - add last_error_txt() and last_except_txt() for produce human readable status.
 - add EXP_TXT, EXP_DETAILS and MB_ERR_TXT dicts to constants (text representation of codes).
 - update of the compatibility test for python version: remove 2.6/3.2/3.3, add 3.7/3.8/3.9.
 - conform to PEP 396 (add pyModbusTCP.__version__ field).

Links

• PyPI: https://pypi.org/project/pymodbustcp
• Changelog: https://pyup.io/changelogs/pymodbustcp/
• Repo: https://github.com/sourceperl/pyModbusTCP

[pyup-bot]

Closing this in favor of #440