[ANN] ShareAdd.jl - making easy to import packages from multiple environments

ShareAdd.jl v2.6 is out, with the new macro @usinghere.

This macro activates an environment in the directory of the current script (or its parent directory if the script is located within a src folder) and automatically adds any missing packages to that environment before importing them. This is specifically useful when writing standalone scripts that should self-manage their dependencies.

The addition has been inspired by this discussion and packages cited therein.