chore: Re-simplify IndexVersionType and MessageLevel with c++20

This sets our compiler requirements to gcc 11 and clang 13. If we
forgo the use of `using enum` we can drop to gcc 10 and clang 10 but
that means using `MessageLevel::Enum::Unknown` for direct enum access

Signed-off-by: Rachel Powers <508861+Ryex@users.noreply.github.com>

launcher/minecraft/mod/Mod.cpp

@@ -195,9 +195,9 @@ auto Mod::mcVersions() const -> QString
 auto Mod::releaseType() const -> QString
 {
     if (metadata())
-        return ModPlatform::indexedVersionTypeToString(metadata()->releaseType);
+        return metadata()->releaseType.toString();
 
-    return ModPlatform::indexedVersionTypeToString(ModPlatform::IndexedVersionType::Unknown);
+    return ModPlatform::IndexedVersionType(ModPlatform::IndexedVersionType::Unknown).toString();
 }
 
 auto Mod::description() const -> QString