* gdcm: 3.0.8 -> 3.0.9
- make use of VTK optional (enabled by default)
- use vtk instead of vtk_7
- fetching source code from GitHub (sourceforge doesn't have the last
version).
- nixpkgs-fmt
* Update pkgs/development/libraries/gdcm/default.nix
* Update pkgs/development/libraries/gdcm/default.nix
Co-authored-by: Sandro <sandro.jaeckel@gmail.com>