1.18.0_nv2: Add runtime to 3.5 schema

Using nvidia-docker2 based off of docker#5360

1.18.0_nv

Updated nvidia-release script to work for future uses

1.17.0_nv

Fixed nil (None) case

1.17.0-rc1-nv

Fixed nil (None) case

1.15.0_nv

Fix error when using multiple volume drivers

1.13.0_nv

Added nvidia-docker support

Signed-off-by: Andy Neff <[email protected]>