[tz] Sao Tome Principe change of time zone

[Steffen Thorsen]

Multiple sources tell that Sao Tome changed from UTC to UTC+1 as they 
entered the year 2018:
https://www.dn.pt/lusa/interior/relogios-avancam-uma-hora-em-sao-tome-e-principe-a-partir-de-janeiro-de-2018-9006615.html
http://pt.rfi.fr/sao-tome-e-principe/20180101-sao-tome-e-principe-muda-de-hora-e-moeda-em-2018
http://www.stp-press.st/2017/12/23/sao-tome-e-principe-vai-mudar-hora-a-partir-de-2018/

So it seems the Africa/Sao_Tome zone needs to activated again!

Our English summary:
https://www.timeanddate.com/news/time/sao-tome-principe-time-zone-change.html

Best regards,
Steffen Thorsen - timeanddate.com