Reduce dependencies - call yahoo finance api directly (#23)
* add notes
* use yfinance api directly - iterate through all timestamps
* remove unused code
* refactor variables
* test two tickers
* remove unused code in conftest
* remove unused dependencies
* remove notes.txt
* add type hint
* add return type for new_calculate_percentage_price_change_over_n_days
* rename function
* reformat
* make work for crypto - all days trading days
* reformat
* use datetime.utcnow to prevent timezone errors
* throw error if yahoo finance api returns non-utc timezone info
* remove comments
* refactor - only catch TimeZoneError
* refactor test name
