Shukla means bright.
Krishna means dark. Krishna is also called Krishna because he is dark.
The Krishna Yajur Veda is the dark, the Shukla Yajur Veda is the bright Yajur Veda.
Shukla Paksha is the bright phase, Krishna Paksha is the dark phase of the moon.
So the term krishna does not necessarily have to do with God Krishna.