Update `test_psm3.csv`

[cwhanse]

Describe the bug
The NSRDB has changed timestamps for TMY files from beginning-of-hour to mid-hour, e.g., from 12:00 to 12:30 for the hour between 12:00 to 13:00. test_psm3.csv should be updated to reflect the NSRDB change. #731 is relevant.

Versions:

• pvlib.__version__: 0.6.3

NSRDB change was made during the week of 5/20/2019.

[cwhanse]

@mikofski got word from NREL, the 30 minute change in TMY timestamps is a permanent change to the NSRDB. NREL doesn't currently have a notification process for these changes, they are aware of that need.