Hello I have found that this library does not support milliseconds of GPS time.

I have created an issue but no update yet so I made my fix to add miliseconds in this library.

GlobalTop PMTK Command packet documentation from Adafruit suggests that reading NMEA can be set up to 10Hz. Therefore, we are able to read GPS time in precision of 100 milliseconds.

I have updated the examples accordingly as well. If you want to test it, don't forget to set the update rate using PMTK220 command. For example,

gps = adafruit_gps.GPS(uart, debug=False)
# gps = adafruit_gps.GPS_GtopI2C(i2c, debug=False)
gps.send_command(b"PMTK220,100")