Fix pandas warning when retrieving quotes.

[difelice]

Issue

Retrieving quotes by indexes but not using pandas iloc method, which show a warning:

FutureWarning: Series.__getitem__ treating keys as positions is deprecated. In a future version, integer keys will always be treated as labels (consistent with DataFrame behavior). To access a value by position, use `ser.iloc[pos]`
  if not _np.isnan(quotes["High"][n - 1]):

Changes

• Modified yfinance/utils.py to fix an issue with retrieving live data from Yahoo Finance.
• Replaced the use of square brackets with the iloc method to access specific elements in the DataFrame.
• Updated the code to use iloc instead of indexing with column names.