[patches] Add cpp20 fix for opm-grid
What this MR does / why does DuMux need it:
The 2024.10 release of OPM-grid is not fully compatible with C++20. https://github.com/OPM/opm-grid/pull/781 resolves the incompatibility as far as DuMux (the test suite) requires. This MR adds the fix to the opm_grid_2024_10.patch
patch.
Edited by Timo Koch