PUBLISH: 13th April 2021 (B)

[pandas] update pandas to use yfinance and minor edits (#133)

* update pandas to use yfinance and minor edits

* fix read function for yahoo finance

* remove margin as not supported in quantecon-book-theme

* add a space for title

PUBLISH: 13th April 2021

publish-2021apr13

harmonise publishing workflows to new QuantEcon workflow (#132)