ci(newline): Fix missing newline at end of bollinger.py

fix lint spacing

Author: ayushkrtiwari

src/quant_research_starter/factors/bollinger.py

@@ -26,4 +26,4 @@ def compute(self, prices: pd.DataFrame) -> pd.DataFrame:
         # Save results
         self._values = zscore
 
-        return zscore
+        return zscore