Wrap update_fsl_package

I think it makes sense for this binary to be easily available or is this considered a too advanced feature to expose like this?

meta.yaml

@@ -5,7 +5,7 @@
 {% set name       = 'fsl-base' %}
 {% set version    = '2306.1' %}
 {% set repository = 'https://git.fmrib.ox.ac.uk/fsl/base.git' %}
-{% set build      = '0' %}
+{% set build      = '1' %}
 
 package:
   name:    {{ name }}