hardcoded version of easi in CMakeLists

[Thomas-Ulrich]

See https://github.com/SeisSol/easi/blob/master/CMakeLists.txt#L4-L6

Leading to this kind of issue:

(base) ulrich@kernelpanic:/export/dump/ulrich/rapid-earthquake-dynamics$ python
Python 3.11.6 | packaged by conda-forge | (main, Oct  3 2023, 10:40:35) [GCC 12.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import easi
>>> print(easi.__file__)
/import/exception-dump/ulrich/myLibs/spack-packages/linux-zen2/easi-1.6.1-aj67wgc3ghbtpbcrigaasmd3b2eyd23z/lib/python3.11/site-packages/easilib/cmake/easi/python_wrapper/easi.cpython-311-x86_64-linux-gnu.so
>>> print(easi.__version__)
1.5.0
>>> 

[davschneller]

Ok that's awkward. We really didn't update the version there?

I'd say that having the version in CMake is normally cleaner than relying on Git.

So maybe, we could check (via CI) if a tagged version like we're having there exists already and is unequal to our current commit. If so, then we'll need to make the CI warn us. Or maybe there are other ideas?

[davschneller]

(other than that, we can merge #82 and publish v1.6.2 for a short-term solution)