Update usage example.

README.md

@@ -14,11 +14,11 @@ csv2json is a fast utility that converts CSV files into JSON line files.
 # 272376070,1063969,"EURINR21DECFUT","","EURINR",0,"2021-12-29",0,0.0025,1,"FUT","BCD-FUT","BCD"
 # ...
 
-$ ./csv2json -i million_rows.csv  > out.json
-Reading million_rows.csv ...
-Processed 1000000 lines in 1.20 seconds (832453.72 lines / second)
+$ ./csv2json -i /tmp/1mil.csv > /tmp/1mil.json                                
+Reading /tmp/1mil.csv ...
+Processed 1000000 lines in 884.61 milliseconds (1000000.00 lines / second)
 
-$ head -n out.json
+$ head -n /tmp/1mil.json
 {"instrument_token": 272376070, "exchange_token": 1063969, "tradingsymbol": "EURINR21DECFUT", "isin": null, "name": "EURINR", "last_price": 0, "expiry": "2021-12-29", "strike": 0, "tick_size": "0.0025", "lot_size": 1, "instrument_type": "FUT", "segment": "BCD-FUT", "exchange": "BCD"}
 {"instrument_token": 272086278, "exchange_token": 1062837, "tradingsymbol": "EURINR21NOVFUT", "isin": null, "name": "EURINR", "last_price": 0, "expiry": "2021-11-26", "strike": 0, "tick_size": "0.0025", "lot_size": 1, "instrument_type": "FUT", "segment": "BCD-FUT", "exchange": "BCD"}
 ```