tools/ci.sh: Use pip-install to get latest version of esptool.py.
tools/ci.sh: Use pip-install to get latest version of esptool.py.

Because the version included in xtensa-lx106-elf-standalone.tar.gz needs
Python 2 (and pyserial for Python 2).

Signed-off-by: Damien George <99e6b749acbfbe2a596df99e91d24d6e1fdbee00@micropython.org>

bvernoux/micropython,adafruit/circuitpython,adafruit/circuitpython,bvernoux/micropython,adafruit/circuitpython,adafruit/circuitpython,adafruit/circuitpython,bvernoux/micropython,henriknelson/micropython,henriknelson/micropython,bvernoux/micropython,henriknelson/micropython,henriknelson/micropython,adafruit/circuitpython,bvernoux/micropython,henriknelson/micropython