Feature request: add tarball with source code and submodules

[BKPepe]

Unfortunately, GitHub does not provide source code tarballs with submodules when using releases. Related https://github.com/dear-github/dear-github/issues/214

I propose to do something similar as was proposed in other projects like:

• https://github.com/AcademySoftwareFoundation/MaterialX/issues/317#issuecomment-560131043
• https://github.com/Goddard-Fortran-Ecosystem/pFUnit/issues/101

[heiher]

Pushed: https://github.com/heiher/natmap/commit/3c3aa44a04d100506d5540267f3b96bc7ec87ead

Thanks for your good idea. @BKPepe

Cc: @ysc3839