ensure FSL 6.0.6 installation works

[kaczmarj]

fsl 6.0.6 utilitizes a new python installer script. while we do not use the installer, we should verify that the installation works the way we expect.

related to #523

[ghisvail]

I'd be happy to work on it. This is what's available through the new installer located at:

https://fsl.fmrib.ox.ac.uk/fsldownloads/fslconda/releases/fslinstaller.py

> python3 fslinstaller.py -h
FSL installer version: 3.5.0
Press CTRL+C at any time to cancel installation
usage: fslinstaller.py [-h] [-v] [-d DESTDIR] [-o] [-l] [-n] [-s] [-m] [-V FSLVERSION]

options:
  -h, --help            show this help message and exit
  -v, --version         Print installer version number and exit
  -d DESTDIR, --dest DESTDIR
                        Install FSL into this folder (default: /Users/johndoe/fsl)
  -o, --overwrite       Delete existing destination directory if it exists, without asking
  -l, --listversions    List available FSL versions and exit
  -n, --no_env          Do not modify your shell or MATLAB configuration (implies --no_shell and --no_matlab). When running the installer script as the root user, the root shell profile is never modified.
  -s, --no_shell        Do not modify your shell configuration
  -m, --no_matlab       Do not modify your MATLAB configuration
  -V FSLVERSION, --fslversion FSLVERSION
                        Install this specific version of FSL

~/Downloads via 🐍 v3.10.10

❯ python3 fslinstaller.py -l
FSL installer version: 3.5.0
Press CTRL+C at any time to cancel installation
Installation log file: /var/folders/m3/r24ql8bj2h9_g1d970f9mr40000w73/T/fslinstaller_caon1_mb.log

Available FSL versions:
6.0.6
  linux-64 https://fsl.fmrib.ox.ac.uk/fsldownloads/fslconda/releases/fsl-6.0.6_linux-64.yml
  macos-64 https://fsl.fmrib.ox.ac.uk/fsldownloads/fslconda/releases/fsl-6.0.6_macos-64.yml
6.0.6.1
  macos-64 https://fsl.fmrib.ox.ac.uk/fsldownloads/fslconda/releases/fsl-6.0.6.1_macos-64.yml
  linux-64 https://fsl.fmrib.ox.ac.uk/fsldownloads/fslconda/releases/fsl-6.0.6.1_linux-64.yml
6.0.6.2
  macos-64 https://fsl.fmrib.ox.ac.uk/fsldownloads/fslconda/releases/fsl-6.0.6.2_macos-64.yml
  linux-64 https://fsl.fmrib.ox.ac.uk/fsldownloads/fslconda/releases/fsl-6.0.6.2_linux-64.yml
6.0.6.3
  macos-64 https://fsl.fmrib.ox.ac.uk/fsldownloads/fslconda/releases/fsl-6.0.6.3_macos-64.yml
  linux-64 https://fsl.fmrib.ox.ac.uk/fsldownloads/fslconda/releases/fsl-6.0.6.3_linux-64.yml
  macos-M1 https://fsl.fmrib.ox.ac.uk/fsldownloads/fslconda/releases/fsl-6.0.6.3_macos-M1.yml
6.0.6.4
  macos-64 https://fsl.fmrib.ox.ac.uk/fsldownloads/fslconda/releases/fsl-6.0.6.4_macos-64.yml
  linux-64 https://fsl.fmrib.ox.ac.uk/fsldownloads/fslconda/releases/fsl-6.0.6.4_linux-64.yml
  macos-M1 https://fsl.fmrib.ox.ac.uk/fsldownloads/fslconda/releases/fsl-6.0.6.4_macos-M1.ym

[ghisvail]

I was able to generate an image with FSL 6.0.6.4 🥳

PR to follow soon.