v0.21.8

RRTMGP v0.21.8

Diff since v0.21.7

Merged pull requests:

• update ClimaCoupler env for downstream test (#596) (@juliasloan25)
• add downgrade test (#597) (@juliasloan25)
• Allow CUDA.jl v6 (#598) (@giordano)

Closed issues:

• Generalize tolerances (#56)
• Add per-grid-point capability (#178)
• Improve memory management (#179)
• Remove magic indexes (#184)
• Make all returned arguments the first one (#192)
• Add documentation for data files (#228)
• Flame graphs times out on builkite (#519)