BUG: Use of deprecated pandas function

[Lucas Lofaro]

finvizfinance version checks

• I have checked that this issue has not already been reported.

• I have confirmed this bug exists on the master branch of finvizfinance.

Reproducible Example

def scan():
    overview = Overview()
    overview.set_filter(filters_dict={
        'Price': 'Over $15',
        'Average Volume': 'Over 2M',
        'Average True Range': 'Over 1.5',
    })
    return overview.screener_view()

Issue Description

This spits out warnings about using append() as it has been deprecated in favor of concat()

frame.append method is deprecated and will be removed from pandas in a future version.

Expected Behavior

Should not use deprecated method.

Installed Versions

0.14.1