Replace std::random_shuffle with std::shuffle

[nyllet]

random_shuffle was removed in c++17

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[Alayan-stk-2]

Thanks for the PR.

As-is, however, it fails to pass some our CI checks.

[nyllet]

hi

As-is, however, it fails to pass some our CI checks.
yes, i think it's because i changed from gnu++0x to c++11. i'll revert that and hopefully it builds on mingw as well

[kimden]

If you continue working on that, please test afterwards whether the online gameplay is unaffected — there was a case before when something was accidentally changed in random generators, and 'updated' servers/clients had different items from the 'old' ones. (If I'm not mistaken, something was postponed to the next major release even because of that.)