Release tarballs missing vendor folder

[eenagy]

Bug Description
Release tarballs are missing the full source code. Although vendor folders are managed by git submodules, the release tarballs should provide a complete and reproducible source code that can be built independently. Currently, it is possible to build from the release tarball (if I tar it myself after git clone), but the absence of vendor folders creates issues.

This becomes a significant problem because git submodules are periodically updated. For instance, two weeks ago, one of the managed submodules was force-pushed, making it impossible to determine the exact source code the client was built from.

Steps to Reproduce

1. Download the release tarball from Nimbus-eth2 v24.4.0.
2. Extract the tarball.
3. Notice that the vendor folder is missing.