BVMF: force open on November 20, 2020

[DStalkerBR]

Mark November 20, 2020 as a trading day in the BVMF calendar, despite it being a holiday under normal circumstances.

In 2020, the São Paulo city government rescheduled Black Awareness Day to May 20 as part of COVID-19 emergency measures. However, B3 did not observe either the original (Nov 20) or the rescheduled (May 20) date as a holiday, remaining open on both.

Source:
https://valorinveste.globo.com/mercados/renda-variavel/noticia/2020/06/08/b3-anuncia-que-vai-abrir-nos-feriados-de-9-de-julho-e-20-de-novembro.ghtml
http://cnnbrasil.com.br/economia/financas/b3-tera-pregao-nesta-sexta-20-apesar-de-feriado-em-sao-paulo/

Workflow to modify an existing Exchange Calendar

• Modify calendar class as required.
• Modify the test resources file (e.g tests/resources/{Exchange MIC}.csv), either manually or by executing python etc/make_exchange_calendar_test_csv.py {Exchange MIC}.
• Check if any of the fixtures in tests/test_{Exchange MIC}_calendar.py need updating to reflect your changes.
• Add references to any new/modified holidays in exchange_calendars/exchange_calendar_{Exchange MIC}.py.