Fix errors in Taiwan

[systemcatch]

closes #2011

(EM) chris@ThinkPad:~/electricitymap$ python parsers/TW.py
{'zoneKey': 'TW', 'datetime': datetime.datetime(2019, 10, 5, 3, 40, tzinfo=tzfile('/usr/share/zoneinfo/Asia/Taipei')), 'production': {'coal': 9611.8, 'gas': 10298.1, 'oil': 501.90000000000003, 'hydro': 581.6999999999999, 'nuclear': 3831.6000000000004, 'solar': 0.0, 'wind': 11.799999999999999, 'unknown': 557.0}, 'capacity': {'coal': 13097.2, 'gas': 16866.4, 'oil': 2572.1, 'hydro': 2091.4999999999995, 'hydro storage': 2602.0, 'nuclear': 3872.0, 'solar': 3144.4, 'wind': 710.9999999999999, 'unknown': 623.2}, 'storage': {'hydro': 1781.8000000000002}, 'source': 'taipower.com.tw'}

[systemcatch]

I'm guessing circleci doesn't support pandas 0.25.1 yet, I will downgrade it back to 0.24.2

[corradio]

@systemcatch pandas 0.25.1 is only for python3. Maybe we should change the circle commands to pip3?

[jarek]

Please do, Python 2 and anything associated is going to be EOL real soon now