mnt/rel-2101.3

This merge request was triggered by a new tag being added to the fsl/base project.

Accepting this merge request will cause the conda recipe for base to be updated to version 2101.3.

If all goes well, a new conda package will built for base (2101.3), and will be uploaded to the FSL production conda channel.

(MR automatically generated by fsl-ci-rules running on the fsl/base repository).