Suggest to loosen the dependency on backtrader

[Agnes-U]

Hi, your project sentiment-fear-and-greed(commit id: 6236690) requires "backtrader==1.9.74.123" in its dependency. After analyzing the source code, we found that the following versions of backtrader can also be suitable, i.e., backtrader 1.9.70.122, 1.9.71.122, 1.9.72.122, since all functions that you directly (7 APIs: backtrader.strategy.Strategy.init, backtrader.cerebro.Cerebro.adddata, backtrader.feeds.csvgeneric.GenericCSVData.init, backtrader.cerebro.Cerebro.init, backtrader.cerebro.Cerebro.plot, backtrader.cerebro.Cerebro.addstrategy, backtrader.cerebro.Cerebro.run) or indirectly (propagate to 61 backtrader's internal APIs and 15 outsider APIs) used from the package have not been changed in these versions, thus not affecting your usage.

Therefore, we believe that it is quite safe to loose your dependency on backtrader from "backtrader==1.9.74.123" to "backtrader>=1.9.70.122,<=1.9.74.123". This will improve the applicability of sentiment-fear-and-greed and reduce the possibility of any further dependency conflict with other projects.

May I pull a request to further loosen the dependency on backtrader?

By the way, could you please tell us whether such an automatic tool for dependency analysis may be potentially helpful for maintaining dependencies easier during your development?