Add TODO for setting API key from environment variable

Added a TODO comment to fetcher.go to set the API key from an environment variable before making the request, ensuring better security and flexibility. Also, removed an unnecessary newline in the main.go file for code cleanliness.

price/fetcher.go

@@ -84,6 +84,7 @@ func fetch(fromTime time.Time, toTime time.Time, period string, logger *zap.Logg
 		return nil, fmt.Errorf("creating request: %w", err)
 	}
 
+	//todo: before making the we need to set this to a env var
 	req.Header.Add("X-Api-Key", "c28c10a82a614930af83a48a3b47189d")
 	resp, err := client.Do(req)
 	if err != nil {