bump codegen version to 0.2.8
bump codegen version to 0.2.8

DualSpark/rust-aws,mattico/rusoto,noggleboggle/rusoto,mattico/rusoto,mattico/rusoto,ford-prefect/rusoto,ford-prefect/rusoto,rusoto/rusoto,DualSpark/rusoto,SecurityInsanity/rusoto,DualSpark/rusoto,rusoto/rusoto,DualSpark/rust-aws,SecurityInsanity/rusoto,DualSpark/rust-aws,rusoto/rusoto,indiv0/rusoto,cmsd2/rusoto,mthjones/rusoto,mthjones/rusoto,DualSpark/rusoto