New update_fsl_package script

Dedicated script for updating FSL conda packages. Does not support installation of new packages at this point in time.

Also added the fslipython wrapper for $FSLDIR/bin/ipython

CHANGELOG.md

 # FSL base project changelog
 
 
+
+## 2112.5 (Thursday 30th December 2021)
+
+* New `update_fsl_package` script, for installing new versions of FSL packages.
+
+
 ## 2112.4 (Tuesday 14th December 2021)
 
 * Fixed more issues with the `depend.mk` rule.