If a package needs a revision to fix bugs or add functionality it needs to be updated. First, we create a development environment using
buildenv.sh that contains the environment variables for 
building the pack.
?- pack_install(.).
Next, we can edit the pack sources and rebuild it the chosen build 
tools after running source buildenv.sh to set the 
appropriate environment variables. After validating that the pack works 
as expected follow the instructions in section 
15.5.2.2 to publish the new version.