Core: icon: mdi:weather-partlycloudy not shown after upgrade

[bouwew]

Home Assistant release with the issue:

0.98.0

Last working Home Assistant release (if known):
0.97.2

Operating environment (Hass.io/Docker/Windows/etc.):

Hassio
Component/platform:

Lovelace

Description of problem:
After upgrading to 0.98.0, one icon is not shown on the header:

All the other icons are still there.

I am using the Compact Custom Header.

Problem-relevant configuration.yaml entries and (fill out even if it seems unimportant):

Traceback (if applicable):

Additional information:

[springstan]

I have not updated or checked if this is working in Home Assistant yet, though it seems that the name has changed. Instead of weather-partlycloudy it is now called weather-partly-cloudy according to Materialdesignicons.com

[bouwew]

Yes, that it!
Thank you!