Merge branch 'develop' of https://github.com/theluxaz/freqtrade into main

# Conflicts:
#	freqtrade/freqtradebot.py
#	freqtrade/optimize/backtesting.py

freqtrade/data/dataprovider.py

@@ -149,6 +149,8 @@ class DataProvider:
         Clear pair dataframe cache.
         """
         self.__cached_pairs = {}
+        self.__cached_pairs_backtesting = {}
+        self.__slice_index = 0
 
     # Exchange functions
 

freqtrade/data/history/history_utils.py

@@ -197,7 +197,8 @@ def _download_pair_history(pair: str, *,
                                                timeframe=timeframe,
                                                since_ms=since_ms if since_ms else
                                                arrow.utcnow().shift(
-                                                   days=-new_pairs_days).int_timestamp * 1000
+                                                   days=-new_pairs_days).int_timestamp * 1000,
+                                               is_new_pair=data.empty
                                                )
         # TODO: Maybe move parsing to exchange class (?)
         new_dataframe = ohlcv_to_dataframe(new_data, timeframe, pair,