Run some stress tests over `investpy.get_stock_historical_data`

[alvarobartt]

According to what was mentioned in #467 and in a lot more issues, due to the high usage of investpy to retrieve data from Investing.com, the HTTP error with code 429 appears. This is actually due to the internal limitations of Investing.com as mentioned in the past, which ends up on your IP getting blacklisted, so that your IP is blocked during some time.

So on, so as to at least have an estimation on how many requests can be sent without getting blacklisted, I'll prepare a simple stress test to check how many consecutive requests can be sent to Investing.com before actually receiving the 429 error code instead of 200.