We'd like to use a consistent checksum scheme everywhere so that we can:
a) incorporate archive checksums into our specs and have a
consistent hashing algorithm across all specs.
b) index mirrors with a consistent type of checksum, and not one that
is dependent on how spack packages are written.
- [x] convert existing md5, sha224, sha512, sha1 checksums to sha256
- remove the old LGPL license headers from all files in Spack
- add SPDX headers to all files
- core and most packages are (Apache-2.0 OR MIT)
- a very small number of remaining packages are LGPL-2.1-only
* automake: added version 1.16.1
* lmod: added version 7.7.29
* git: added version 2.17.0
* tmux: added version 2.7
* scala: added version 2.12.5, fixed typo in version 2.10.6
* Added spark@2.3.0, hadoop@3.1.0, jdk@8u172-b11
* picard: added version 2.18.3
* tar: added version 1.30
