Install script shell

[lassepe]

The first few lines of the install_singularity.sh script switch to the shell that is set in the user's SHELL variable. For users that don't use a POSIX compliant shell, such as FISH, this can cause issues (and it did for me). I worked around this by explicitly setting SHELL=/bin/bash for the install procedure. However, unless otherwise needed, it may be advisable to just set an appropriate shebang on top of the script that enforces the correct shell instead of loading the users shell.

[klaxalk]

Ye, you are right. This is there solely for the reason of setting up the GO environment variables. I will think of an alternative solution to this. Thanks