This commit partially reverts ce3d6a91d (Convert external projects to zips)
It avoids check-sum verification failure in the following scenarios:
the branch with the patches is updated to include additional patches.
the git server re-generate the cached archives with a new approach leading to different checksums. see [1], [2] and [3] for discussion of similar issues with eiter GitLab or GitHub
It also references the branch imstk-v3.3.1-2016-07-08-a8673d482 (equivalent to fixCompilationError). The associated naming convention is documented at https://gitlab.kitware.com/iMSTK/assimp/-/blob/welcome/README.md
[1] Gitlab release tarball stability https://forum.gitlab.com/t/gitlab-release-tarball-stability/41888
[2] Why are the md5 checksums for download archives different? https://forum.gitlab.com/t/why-are-the-md5-checksums-for-download-archives-different/41649/2
[3] Github Archive URL checksums have changed https://github.com/spack/spack/issues/5411