Add support for Omron B3U-1000P (2.5x3mm tactile switch top)

[ceoloide]

Ref: https://www.snapeda.com/parts/B3U-1000P/Omron/view-part/
Shop: https://keebd.com/en-us/products/2-5x3mm-b3u-1000p-dip-push-button-switch