fix(slides): correct date type in historical exchange rate example

Use `LocalDate` instead of `LocalDateTime` to align with
Moneta/ECB-HIST expectations for date-based queries.

slides/slides.md

@@ -676,7 +676,7 @@ MonetaryAmount amountCHF = Money.of(10, "CHF");
 
 ConversionQuery query = ConversionQueryBuilder.of()
     .setTermCurrency("EUR")
-    .set(LocalDateTime.class, LocalDateTime.of(2026, 3, 13, 14, 3, 27))
+    .set(LocalDate.class, LocalDate.of(2026, 3, 13))
     .build();
 
 CurrencyConversion conversion = MonetaryConversions.getConversion(query);