comms/py-esptool: Update to 2.5.1

[loader]

Summary

Proposed commit log message:

comms/py-esptool: Update to 2.5.1

Changelog:

  https://github.com/espressif/esptool/releases/tag/v2.5.1
  
Reviewed_by: koobs
Approved by: koobs (mentor)
Differential_Revision: D18619

Test Plan

• portlint: OK (

WARN: Makefile: possible use of absolute pathname "/dev/ttyU0".
0 fatal errors and 1 warning found.
)

• testport: OK (poudriere: 1300004, [armv7, aarch64], 'BUILD_ALL_PYTHON_FLAVORS=1', [py27, py35, py36, py37] tested)
• unittest: OK (

Tested ESP8266 with CP2102 USB serial adapter on Raspberry Pi 3B (aarch64)
Python2.7: pytest: 56 passed, test_esptool.py: 41 passed
Python3.5: pytest: 56 passed, test_esptool.py: 40 passed 1 failed
Python3.6: pytest: 56 passed, test_esptool.py: 40 passed 1 failed
Python3.7: pytest: 56 passed, test_esptool.py: 40 passed 1 failed
)

[koobs]

Looks good!

[loader]

Thanks @koobs.