v0.6.3

KernelAbstractions v0.6.3

Diff since v0.6.2

Merged pull requests:

• nix overdub of _unsafe_getindex (#247) (@vchuravy)
• Stop overdubbing CUDA math functions (#249) (@ali-ramadhan)
• Backport #249 (#251) (@vchuravy)
• Check pow overdubbing (#253) (@vchuravy)