text: Title: Zig Zag Indicator
  Body: Hi, 
  pandas_ta is a fantastic project, thanks for sharing it.
  
  Maybe it si a good idea to implement the Zig-Zag indicator.
  It is a indicator that is nog based on periods but on % of change.
  On this way will be easy to find the higest and lowest pivot points in the past.
  It is also great to see the trend is up or down.
  In the link below the indicator is explained:
  [https://www.investopedia.com/terms/z/zig_zag_indicator.asp](url)
  