Updated flake.lock to bring symengine-0.12.0 into nix

[jake-arkinstall]

… the patch file to fit

Description

To keep the nix build in sync, symengine needed updating. Fortunately the flake tracks nixpkgs' master branch, which has had symengine 0.12 for a week. So a nix flake update handled that.

Additionally, as we patch symengine to have it expose symengine libraries through INTERFACE_LINK_LIBRARIES, the patch file needed adjusting to take into account the new symengine's cmake/SymEngineConfig.cmake.in file.

I have run the tests on my local linux machine.

Related issues

N/A

Checklist

• [x] I have performed a self-review of my code.
• [-] I have commented hard-to-understand parts of my code.
• [-] I have made corresponding changes to the public API documentation.
• [-] I have added tests that prove my fix is effective or that my feature works.
• [-] I have updated the changelog with any user-facing changes.