Fix potential compatibility with C++20 / C++23 mode

This fixes several issues with compatibility with C++20. C++23 was also
tested, but apparently it does not have any additional breaking changes
compared to C++20 (or we don't have those).

VCMI still uses C++17 as before - goal is only to make potential
transition easier.

There were 2 cases that are deprecated in C++20 that we use:
- Floating point operations on enums are deprecated
- `this` can no longer be captured when using default capture by value
`[=]`

Both of those should now be replaced with code that works fine in both C+
+17 and in C++20 mode

lib/gameState/CGameState.cpp

@@ -1264,7 +1264,7 @@ EVictoryLossCheckResult CGameState::checkForVictoryAndLoss(const PlayerColor & p
 	const MetaString messageLostSelf = MetaString::createFromTextID("core.genrltxt.7");
 	const MetaString messageLostOther = MetaString::createFromTextID("core.genrltxt.8");
 
-	auto evaluateEvent = [=](const EventCondition & condition)
+	auto evaluateEvent = [this, player](const EventCondition & condition)
 	{
 		return this->checkForVictory(player, condition);
 	};