Dockerfile keeps pointing to elderly dcm2niix; Mess among container "versions" flavors

[yarikoptic]

Dockerfile in this repo nicely and reproducibly installing elderly v1.0.20190410

$> docker run -it --rm --entrypoint dcm2niix nipy/heudiconv:0.9.0
Chris Rorden's dcm2niiX version v1.0.20190410  GCC6.3.0 (64-bit Linux)

To add to the insult we also provide reproin-built heudiconv containers and those ATM seems to carry different dcm2niix between docker and singularity builds (although should be from the same recipe):

$> docker run -it --rm --entrypoint dcm2niix repronim/reproin:0.9.0
Chris Rorden's dcm2niiX version v1.0.20200427  (JP2:OpenJPEG) GCC8.3.0 (64-bit Linux)

$> singularity exec shub://ReproNim/reproin:0.9.0 dcm2niix
Chris Rorden's dcm2niiX version v1.0.20201102  (JP2:OpenJPEG) GCC8.3.0 x86-64 (64-bit Linux)

poor users and us uff...